Important tune up information
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Postmaster
Joined: Oct 2009
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Important tune up information
Ok, here is a common story. A user wants to tune up the Aerostar to help it run better, and get better gas mileage. So they run to the auto parts store, grab a set of plugs, wires, and a cap and rotor (if applicable). They spend the next hour or two busting their knuckles in the limited space, but finally they are done. Then a couple days, weeks, or months later, they start noticing decreased performance and maybe a miss. They try to figure out what is wrong, only to eventually conclude that a plug or wire was the culprit. They decide maybe the parts they used were too cheap, so they get a more expensive wire set, and maybe some of those twin tip or quad tip plugs that were promoted at the parts store. After busting up the knuckles a second time, everything is great, for a while. Then it starts running even worse than before. What has gone wrong?
The Basics
Ford has engineered their ignition systems very precisely. For a reference, lets start with how the system works. There are going to be some differences between the conventional distributor based system and the distributor-less (coil pack) systems. Lets begin with the first.
Distributor Based Systems (non-EDIS)
The 3.0L used the distributor type system up till '96. So most '95 and older 3.0L equipped systems have this type of ignition. Much of this also applies to the older 2.3L and 2.8L engines. The system uses an ignition module, most often located on the passenger side fender, though earlier models had it mounted directly on the distributor. This module basically reads the PIP signal from the distributor, and combined with information from the computer, it fires the coil. The coil contains two sets of windings. The low voltage winding operates at 12 volts. As current flows through this winding, the changing magnetic field that is produced induces a second higher voltage current that then travels through the primary ignition wire to the rotor inside the distributor. From there it has to jump a gap to the correct terminal on the cap. Then it travels down the appropriate wire to the plug, where it jumps a gap there, and ignites the mixture.
While this all seems simple, the specifications involved are very precise, especially since the current must jump two gaps and looses energy every time it does so. Ford engineered this very precisely. We will come back to this later as what makes this tricky is similar to the EDIS setup.
EDIS Systems
The 4.0L came equipped with the EDIS system which produced more spark energy and got rid of the cap and rotor which wore out over time. The system is what is called a waste spark system. This system uses a single coil to fire pairs of cylinders. The spark fires on both cylinders at the same time, one on the ignition phase, the other on the exhaust phase. This system works the plugs and wires twice as hard as a normal ignition system, so the plugs have to be able to handle the extra workload, and the wires must also be very tough. While the energy for the spark is supplied differently, some of the specifications that make these systems tricky are the same for the distributor based systems. The thing that is different from the non-EDIS systems is the flow direction of the spark energy. Starting with the coil, energy flows down one wire, through the plug where it jumps the gap from the tip to the electrode, then through the block ground, to the other plug on the opposite bank where it jumps from the electrode to the tip, then flows up the other wire and back to the coil, completing the circuit. Because the current is flowing in different directions on each bank, double platinum plugs are the best choice. From the factory, Ford used two different types of single platinum plugs that could not be swapped from one bank to the other. Double platinums takes the guesswork out and are more readily available to the consumer.
Plugs
The spark plug is one of the most critical components in the engine. This is where the spark energy is released to ignite the fuel air mixture in the chamber. There are a number of factors that need to come together to make this happen properly, and gap is not the only factor. Most plugs in the parts store match the original gap and reach of the plug, but do not match the heat range, displacement, durability, or technical specifications of the original plug. As a result, this means a number of problems can stem from using the wrong plug. If the heat range is too high, then you will get pinging, accelerated wear, decreased performance, decreased fuel economy, and misfires. Same with many of the other factors. The tip and electrode can be made from various materials. Cheaper plugs are typically made from copper alloys. These are not for use in Aerostars. Conventional distributor based systems should use a single or double platinum plug. In this application, double platinum offers no real advantages, but it doesn't hurt. EDIS systems MUST use double platinum or iridium plugs.
Many parts stores promote these multiple electrode plugs that offer increased gas mileage, longer wear life, etc. Stay away from these, they are not for Ford engines.
The correct plugs to use are made by Autolite. The Motorcraft plugs are actually made by Autolite, so either will work just fine. The important thing is that they are OE spec, single or double platinum for the non-EDIS systems, and double platinum or iridium for the EDIS systems.
Wires
The plugs cannot perform optimally if they cannot get adequate spark energy and that energy is carried by the wires. The wires may seem simple enough, after all, they just have to be conductors right? The wires task is a little more complicated than that. The high voltages they carry can produce strong electromagnetic fields. The fields are strong enough that they can interfere with the other electronic components. So the wires must be able to suppress these fields. This is typically accomplished through the use of a carbon based insulator. The Aerostar uses a very strong ignition coil, and this also puts a dielectric stress on the wires. The wires use a silicone based insulator to provide proper dielectric strength, which prevents the spark from jumping through the insulator to the metal block. The wires also have to connect to the cap or coil packs and to the plugs, so they have shielded connectors. All of these components are potential failure points, and most aftermarket wires are deficient in one or more of these areas. The two most common areas of weakness are the carbon insulators (most aftermarket wires are too high, but are also sometimes too low), and the thermal resistance is inadequate. The result is a wire that works briefly, but fails long before it should.
There are only three brands of wires that consistently work, and one you have to be careful with. Motorcraft is the first obvious one. Autolite makes these wires, however it should be noted that not all Autolite wares are made to the Motorcraft specifications. Make sure you use the Autolite OE spec. Motorcraft wires are usually comparably priced, and often more readily available. The other brand that works is the Magnacor race wires. They use a specialized conductor that carries more current while still providing the required EFI suppression. These are an initially expensive choice, but they last much longer than carbon suppressor wires. If properly cared for, they will be the last set of wires you will ever need.
Cap and Rotor
The function of the cap and rotor is to direct the power to the correct cylinder at the correct time. The problem with cheaper aftermarket units is that they can wear out faster than the OE units, which puts added stress on the coil and decreases the available power to the plugs. This is not the most critical area, but you should still be aware of it. For optimal performance, use OE parts such as Motorcraft.
Coil or Coil Pack
The coil is a fairly simple component. However, there are variations in the construction techniques between cheap aftermarket parts and OE parts. The main difference is in the quality of the windings and in the insulating resin that is used. Cheaper products have thinner or weaker windings and low quality insulating resin that can break down, resulting in decreased energy output. This is not to say that all aftermarket coils are junk, but stay away from the low quality stuff.
Performance coils do not necessarily offer much real world performance, but they can prevent power loss due to weak ignition. Accel and MSD are two good examples. They are descent alternatives to OE coils, though two things should be kept in mind. The increased energy of these coils will put more stress on the rest of the ignition system and can produce accelerated wear of the plugs, wires, cap, and rotor.
Hopefully this sums up what parts to use, what not to use, and why this is. This should probably be a sticky so that new users can find this article easily and hopefully save them from buying the wrong parts.
The Basics
Ford has engineered their ignition systems very precisely. For a reference, lets start with how the system works. There are going to be some differences between the conventional distributor based system and the distributor-less (coil pack) systems. Lets begin with the first.
Distributor Based Systems (non-EDIS)
The 3.0L used the distributor type system up till '96. So most '95 and older 3.0L equipped systems have this type of ignition. Much of this also applies to the older 2.3L and 2.8L engines. The system uses an ignition module, most often located on the passenger side fender, though earlier models had it mounted directly on the distributor. This module basically reads the PIP signal from the distributor, and combined with information from the computer, it fires the coil. The coil contains two sets of windings. The low voltage winding operates at 12 volts. As current flows through this winding, the changing magnetic field that is produced induces a second higher voltage current that then travels through the primary ignition wire to the rotor inside the distributor. From there it has to jump a gap to the correct terminal on the cap. Then it travels down the appropriate wire to the plug, where it jumps a gap there, and ignites the mixture.
While this all seems simple, the specifications involved are very precise, especially since the current must jump two gaps and looses energy every time it does so. Ford engineered this very precisely. We will come back to this later as what makes this tricky is similar to the EDIS setup.
EDIS Systems
The 4.0L came equipped with the EDIS system which produced more spark energy and got rid of the cap and rotor which wore out over time. The system is what is called a waste spark system. This system uses a single coil to fire pairs of cylinders. The spark fires on both cylinders at the same time, one on the ignition phase, the other on the exhaust phase. This system works the plugs and wires twice as hard as a normal ignition system, so the plugs have to be able to handle the extra workload, and the wires must also be very tough. While the energy for the spark is supplied differently, some of the specifications that make these systems tricky are the same for the distributor based systems. The thing that is different from the non-EDIS systems is the flow direction of the spark energy. Starting with the coil, energy flows down one wire, through the plug where it jumps the gap from the tip to the electrode, then through the block ground, to the other plug on the opposite bank where it jumps from the electrode to the tip, then flows up the other wire and back to the coil, completing the circuit. Because the current is flowing in different directions on each bank, double platinum plugs are the best choice. From the factory, Ford used two different types of single platinum plugs that could not be swapped from one bank to the other. Double platinums takes the guesswork out and are more readily available to the consumer.
Plugs
The spark plug is one of the most critical components in the engine. This is where the spark energy is released to ignite the fuel air mixture in the chamber. There are a number of factors that need to come together to make this happen properly, and gap is not the only factor. Most plugs in the parts store match the original gap and reach of the plug, but do not match the heat range, displacement, durability, or technical specifications of the original plug. As a result, this means a number of problems can stem from using the wrong plug. If the heat range is too high, then you will get pinging, accelerated wear, decreased performance, decreased fuel economy, and misfires. Same with many of the other factors. The tip and electrode can be made from various materials. Cheaper plugs are typically made from copper alloys. These are not for use in Aerostars. Conventional distributor based systems should use a single or double platinum plug. In this application, double platinum offers no real advantages, but it doesn't hurt. EDIS systems MUST use double platinum or iridium plugs.
Many parts stores promote these multiple electrode plugs that offer increased gas mileage, longer wear life, etc. Stay away from these, they are not for Ford engines.
The correct plugs to use are made by Autolite. The Motorcraft plugs are actually made by Autolite, so either will work just fine. The important thing is that they are OE spec, single or double platinum for the non-EDIS systems, and double platinum or iridium for the EDIS systems.
Wires
The plugs cannot perform optimally if they cannot get adequate spark energy and that energy is carried by the wires. The wires may seem simple enough, after all, they just have to be conductors right? The wires task is a little more complicated than that. The high voltages they carry can produce strong electromagnetic fields. The fields are strong enough that they can interfere with the other electronic components. So the wires must be able to suppress these fields. This is typically accomplished through the use of a carbon based insulator. The Aerostar uses a very strong ignition coil, and this also puts a dielectric stress on the wires. The wires use a silicone based insulator to provide proper dielectric strength, which prevents the spark from jumping through the insulator to the metal block. The wires also have to connect to the cap or coil packs and to the plugs, so they have shielded connectors. All of these components are potential failure points, and most aftermarket wires are deficient in one or more of these areas. The two most common areas of weakness are the carbon insulators (most aftermarket wires are too high, but are also sometimes too low), and the thermal resistance is inadequate. The result is a wire that works briefly, but fails long before it should.
There are only three brands of wires that consistently work, and one you have to be careful with. Motorcraft is the first obvious one. Autolite makes these wires, however it should be noted that not all Autolite wares are made to the Motorcraft specifications. Make sure you use the Autolite OE spec. Motorcraft wires are usually comparably priced, and often more readily available. The other brand that works is the Magnacor race wires. They use a specialized conductor that carries more current while still providing the required EFI suppression. These are an initially expensive choice, but they last much longer than carbon suppressor wires. If properly cared for, they will be the last set of wires you will ever need.
Cap and Rotor
The function of the cap and rotor is to direct the power to the correct cylinder at the correct time. The problem with cheaper aftermarket units is that they can wear out faster than the OE units, which puts added stress on the coil and decreases the available power to the plugs. This is not the most critical area, but you should still be aware of it. For optimal performance, use OE parts such as Motorcraft.
Coil or Coil Pack
The coil is a fairly simple component. However, there are variations in the construction techniques between cheap aftermarket parts and OE parts. The main difference is in the quality of the windings and in the insulating resin that is used. Cheaper products have thinner or weaker windings and low quality insulating resin that can break down, resulting in decreased energy output. This is not to say that all aftermarket coils are junk, but stay away from the low quality stuff.
Performance coils do not necessarily offer much real world performance, but they can prevent power loss due to weak ignition. Accel and MSD are two good examples. They are descent alternatives to OE coils, though two things should be kept in mind. The increased energy of these coils will put more stress on the rest of the ignition system and can produce accelerated wear of the plugs, wires, cap, and rotor.
Hopefully this sums up what parts to use, what not to use, and why this is. This should probably be a sticky so that new users can find this article easily and hopefully save them from buying the wrong parts.
Post Fiend
Joined: Apr 2005
Posts: 5,720
Likes: 5
From: Washington state
if the aftermarket coil pack manuf.s increase the HV output by decreasing the turns or resistance of the primary coil thus increasing the drive current, it increases the chance of coil drivers failure.
expensive proposition, either a new ICM or a new PCM on OBDII systems
i suggest sticking with stock FoMoCo/Motorcraft replacements
all components in the system are designed to work together without overtaxing any individual component.
what usually breaks down in the spark plug ignition wires is the insulation from the high heat levels in the cramped poor air flow Aero engine compartment. insulation breakdown leaks to spark leak especially in wet weather or with road spray.
the Motorcraft wires have some of the highest quality silicone ign. wire insulation on the market and they are a full 8mm dia.
the same wires will last 10 years or more in a wide open Ranger with better air flow
the cheap imports, who knows what they really have as insulation?
expensive proposition, either a new ICM or a new PCM on OBDII systems
i suggest sticking with stock FoMoCo/Motorcraft replacements
all components in the system are designed to work together without overtaxing any individual component.
what usually breaks down in the spark plug ignition wires is the insulation from the high heat levels in the cramped poor air flow Aero engine compartment. insulation breakdown leaks to spark leak especially in wet weather or with road spray.
the Motorcraft wires have some of the highest quality silicone ign. wire insulation on the market and they are a full 8mm dia.
the same wires will last 10 years or more in a wide open Ranger with better air flow
the cheap imports, who knows what they really have as insulation?
Elder User
Joined: Dec 2006
Posts: 830
Likes: 0
From: Kitchener,Ontario,Canada
OEM for a reason.
Great info!
A case in point is spark plugs...... it really is important to put in the correct ones. I tried Bosch platinums & they lasted around 55-60 ,000 kms on the 3 litre EDIS ignition system. The MC plugs lasted almost 200,000 before they started to misfire.And the price difference was negligable! I had to go to Ford to get them though.
If Ford could have found parts with higher specs I'm guessing they would have used them.
A case in point is spark plugs...... it really is important to put in the correct ones. I tried Bosch platinums & they lasted around 55-60 ,000 kms on the 3 litre EDIS ignition system. The MC plugs lasted almost 200,000 before they started to misfire.And the price difference was negligable! I had to go to Ford to get them though.
If Ford could have found parts with higher specs I'm guessing they would have used them.
Lead Driver
Joined: Sep 2003
Posts: 7,013
Likes: 205
From: SoCal
if the aftermarket coil pack manuf.s increase the HV output by decreasing the turns or resistance of the primary coil thus increasing the drive current, it increases the chance of coil drivers failure.
expensive proposition, either a new ICM or a new PCM on OBDII systems
expensive proposition, either a new ICM or a new PCM on OBDII systems
You can protect ignition modules with something like an MSD ignition modulator. It provides a reduced load for the coil drivers in the ignition module, and then amplifies the signal, and does other things with it, like the multiple spark discharge with higher voltages. Also, the MSD actually turns the coil into a step-up transformer, instead of an energy storage device like in stock ignition systems, so it can fire the multiple sparks with full strength. This provides greater benefits on old point-contact ignition systems, and does very little for a modern, high quality electronic ignition system, except for the module protection. Of course, on a 6 cylinder EDIS system like the Aerostar, you will need 3 of them.
what usually breaks down in the spark plug ignition wires is the insulation from the high heat levels in the cramped poor air flow Aero engine compartment. insulation breakdown leaks to spark leak especially in wet weather or with road spray.
the Motorcraft wires have some of the highest quality silicone ign. wire insulation on the market and they are a full 8mm dia.
the Motorcraft wires have some of the highest quality silicone ign. wire insulation on the market and they are a full 8mm dia.
It's given that the wires have to direct high voltages to the spark plugs and nowhere else. Something that people who buy aftermarket ignition parts that promise "higher voltage" don't realize is that under normal conditions, it takes a particular voltage to jump the gaps in the ignition system. Any additional voltage beyond that is wasted. The wires in theory should not have to protect beyond that voltage. If they do, it usually means something else is wrong, and should be fixed, not band-aided over with a stronger ignition.
There are other cases where they will need the higher voltages, like if they install anything that increases compression pressure (forced induction, new heads, cam, etc.). In those cases, they will also have to fortify their wires to match.
Elder User
Joined: Dec 2006
Posts: 830
Likes: 0
From: Kitchener,Ontario,Canada
My original plug wires went for 11&12 years & still were good. They are now changed though, due to the boots on 2 plugs getting ripped whilst replacing the plugs. I put Niehoff in but now wish I had used OEM.
Postmaster
Joined: Apr 2001
Posts: 3,818
Likes: 3
My '91 4.0 E-4WD came equipped day from one with single electrode platinum plugs and have run with the same replacement plugs all the way to 285,000 miles with no problems. Same plug is used on both banks. There is no mention in the Ford factory manual that it requires any other type of application than as currently equipped.
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Postmaster
Joined: Oct 2009
Posts: 3,432
Likes: 7
I have personally seen the effects of single platinums on an EDIS system. My brothers van had Motorcraft single platinums when he bought it. The PO said he had changed them only 20,000 earlier. About a month after he bought it, CEL comes on with cylinder 4 misfire. I changed the plugs for him, found all the passenger side plugs looks pristine, but the drivers side plugs, all three looked like they had been on there for over 100,000 miles. What happens is the current was jumping from the copper alloy to the platinum, and was vaporizing the cooper as it did so. The platinum resists it. So I have seen this happen personally. And it didn't just do it to one, all three were equally affected. The double platinums do last longer too. My last set ran 90,000 miles, and they looked like they were at about half life. I replaced them anyway.
The Ford manual doesn't mention it because the plugs were developed after the manual was written. Ford has TSBs and product updates that list the updated double platinum part numbers, and Autolite lists the new finewire double platinums as the replacement for the older design.
Sure you can run singles, but you do not want to have to do it over again. For the record, the part# listed in my owners manual is a double platinum. The original plugs that came from the factory are not. The part number from the original plugs is different from the one in the owners manual.
The Ford manual doesn't mention it because the plugs were developed after the manual was written. Ford has TSBs and product updates that list the updated double platinum part numbers, and Autolite lists the new finewire double platinums as the replacement for the older design.
Sure you can run singles, but you do not want to have to do it over again. For the record, the part# listed in my owners manual is a double platinum. The original plugs that came from the factory are not. The part number from the original plugs is different from the one in the owners manual.
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Post Fiend
Joined: Apr 2005
Posts: 5,720
Likes: 5
From: Washington state
not a Ford better idea.
way Ford solved the series plug point erosion on the EDIS systems like the 4L was to have one of the pairs with the platinum tip on the shield strap and the other plug of the pair with the plat. tip on the center electrode of the factory installed OEM plugs.
must have been a nightmare getting them in the right holes at the factory.
the 2 different tip types of plug had a different part numbers.
as far as I've researched, Ford never made these avail aftermarket nor ever spec'd 2 different location type of plat tips for the 4L. they may have been avail. for dealer shop use only until the dual plats came out.
whole write up on the plug fiasco elsewhere in Aero forum.
can you picture a shade tree mechanic with his first 4L Aero pulling all the plugs out, laying them down side by side to check gap and condition and never realizing the plat tip difference as he put them back in, darn plugs burned up after only 30k miles.
sometimes, Ford cheap is not always better
as old Henry would reply to complaints about the Model T, "You've got 2 gears, that's enough for anybody."
way Ford solved the series plug point erosion on the EDIS systems like the 4L was to have one of the pairs with the platinum tip on the shield strap and the other plug of the pair with the plat. tip on the center electrode of the factory installed OEM plugs.
must have been a nightmare getting them in the right holes at the factory.
the 2 different tip types of plug had a different part numbers.
as far as I've researched, Ford never made these avail aftermarket nor ever spec'd 2 different location type of plat tips for the 4L. they may have been avail. for dealer shop use only until the dual plats came out.
whole write up on the plug fiasco elsewhere in Aero forum.
can you picture a shade tree mechanic with his first 4L Aero pulling all the plugs out, laying them down side by side to check gap and condition and never realizing the plat tip difference as he put them back in, darn plugs burned up after only 30k miles.
sometimes, Ford cheap is not always better
as old Henry would reply to complaints about the Model T, "You've got 2 gears, that's enough for anybody."
Lead Driver
Joined: Sep 2003
Posts: 7,013
Likes: 205
From: SoCal
That is still a puzzle why Ford did this. It could not have been cheaper to design and manufacture 2 different plugs and make sure they're correctly installed in the assembly line just to save a little bit of platinum.
Elder User
Joined: Dec 2006
Posts: 830
Likes: 0
From: Kitchener,Ontario,Canada
FTE Community Team
Joined: Nov 2001
Posts: 1,814
Likes: 246
From: Oak Harbor, Washington
This just caught me.
I put AP103s (single platinum) in by mistake nine months/7k miles ago. I'd noticed a couple of times on cold start that it would fire up on five cyls, then a sixth would come online a few seconds later.
Three days ago, getting on the interstate (I am driving 46 miles each way on the highway commute daily for a couple more months), a cylinder dropped out solid, and stayed that way at any higher-load conditions. And, after that, cold starts were five cyls only until completely warmed up.
After inspecting the boots on both ends of the plug wires, I picked up a set of APP103s (double platinum) and changed them out last night. Problem solved.
The AP103s I took out look fine to me. Oh, and I got a code P0301 (cyl. No. 4 misfire) which I only pulled and cleared after I'd changed the plugs. The old plug looks just like the others, and the gaps are all in spec.
I'm only relating this as a confirmation for others: use the correct plugs on the EDIS rigs.
I put AP103s (single platinum) in by mistake nine months/7k miles ago. I'd noticed a couple of times on cold start that it would fire up on five cyls, then a sixth would come online a few seconds later.
Three days ago, getting on the interstate (I am driving 46 miles each way on the highway commute daily for a couple more months), a cylinder dropped out solid, and stayed that way at any higher-load conditions. And, after that, cold starts were five cyls only until completely warmed up.
After inspecting the boots on both ends of the plug wires, I picked up a set of APP103s (double platinum) and changed them out last night. Problem solved.
The AP103s I took out look fine to me. Oh, and I got a code P0301 (cyl. No. 4 misfire) which I only pulled and cleared after I'd changed the plugs
. The old plug looks just like the others, and the gaps are all in spec.I'm only relating this as a confirmation for others: use the correct plugs on the EDIS rigs.
Fleet Mechanic
Joined: Apr 2003
Posts: 1,460
Likes: 6
From: Florida
on some days it runs like a champ after it warms up, it runs great!, then I do my errands, start it again, and back to the misfire/rough running.
it would help me if you posted the correct part numbers for the plugs and wires, maybe they put the wrong plugs and wires?
yes, it has a CEL ON all the time. I went to autozone and got the following Codes:
PO171, PO401, PO302, PO304
I'm doomed! this is too much for a shadetree mechanic like me and I will not take the van to any Ford dealer or independent shop because they will damage my rocker panels and I will not take that risk.
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Postmaster
Joined: Oct 2009
Posts: 3,432
Likes: 7
P0171 means you have a lean code, which most likely means you have a vacuum leak, which can also cause misfires. On the flip side, it could also be caused by misfires.
Feel free to take it to a mechanic, but be very clear that they have to lift it on either a 4 post lift, and have it in writing that they will be responsible for any damage to the van's body panels.
I would start with replacing all vacuum lines, and replace the ignition components as outlined above. Use Motorcraft or Magnacore wires, and use either Autolite, NGK, or Motorcraft double platinum or iridium. If that doesn't fix the mis and lean code, you will need to remove both the upper and lower intake, and replace the gaskets. In the unlikely event that it still doesn't fix those codes, you will need to run a compression test and a leakdown test. It wwouldn't hurt to do a compression and leakdown test anyway, nothing tells you more about the health of the engine itself than to do a compression and leak down.
If the compression is good all around, and the ignition doesn't resolve the issue, you may have a fuel delivery problem.
Feel free to take it to a mechanic, but be very clear that they have to lift it on either a 4 post lift, and have it in writing that they will be responsible for any damage to the van's body panels.
I would start with replacing all vacuum lines, and replace the ignition components as outlined above. Use Motorcraft or Magnacore wires, and use either Autolite, NGK, or Motorcraft double platinum or iridium. If that doesn't fix the mis and lean code, you will need to remove both the upper and lower intake, and replace the gaskets. In the unlikely event that it still doesn't fix those codes, you will need to run a compression test and a leakdown test. It wwouldn't hurt to do a compression and leakdown test anyway, nothing tells you more about the health of the engine itself than to do a compression and leak down.
If the compression is good all around, and the ignition doesn't resolve the issue, you may have a fuel delivery problem.