Hello, I am new to this forum so I apologize if this thread is already talked about somewhere. I could not find it anywhere. So here goes. I took my 2003 F150 to 2 different shops. they both said it had a cylinder misfire in #4. It has the triton 5.4 in it. Shop #1 said that the motor needed to be replaced and shop #2 said that the spark plug needed to be replaced. The truck just started sputtering with the check engine light on before I took it to the shop. After the shops the check engine light went off and it started to act normal. I have only driven it once since then and it drove fine. I don't believe a messed up engine would improve? My question is does anyone know how much it cost to replace the coil, cap, and spark plugs and wires? I would have it done instead of trying to do that myself.

 

I would be that you have a spark plug or coil on plug pack on maybe a connection loose. I doubt your engine needs to be replaced ( mind you , you didnt say what your mileage was)

The 5.4 2v is a very good engine and very reliable. When was the last time you changed all your spark plugs? You say the truck runs normally now? My bet would be the spark plug or the coil on plug pack for cylinder 4 one of the two is starting to have issues.

I would change the spark plug in cylinder 4 first, and have a look at it see what conniption it is in, but you really should just change it out.

Now you can swap the coil on plug packs with the cylinder next to cylinder 4 and put the one from the cylinder beside it on to cylinder 4 and vice versa to see if the coil is the issue or you can just buy one new coil on plug pack and take the other one off cylinder 4 and put in the new spark plug and put the new COP in ( that's coil on plug) back

It's not hard to change the plugs and COP's in the 5.4 2v engine. The COPS that are OEM ( from Ford )run around 38 bucks and spark plugs that are OEM can arrange between 3 to 7 bucks

Now you can buY a full set 8 non OEM coils for between 40 to 80 bucks on ebay amazon parts stores ect ect. as well as single non OEM COP's. Some are good some are garbage you want to make sure you read up on them if you go that route.

Honestly it really isnt that hard to change the plugs and COP's your self, it just takes some time and tools and knowing the correct spark plug gap and torque spec. You could also have it done for you as well. Dont know what the cost would be, because I do mine myself.

You could always ask a friend who is mechanically inclined to give you a hand or ask a shop for a quote. I would skip the guys who told you you need an new engine If you want to change all 8 COPS and plug to give your self peace of mind.

You can always buy the plugs and cops from the Ford dealer as well or online whether you want to go OEM or aftermarket and then take the parts to the shop you choose and got a quote from on just labour and have them do the work and give you the old plugs and cops back or you could just change the one spark plug and COP, that is up to you

If you havent changed plugs at all then I suggest you change all your spark plugs and then you could replace all your COPS as well or just change the COP on cylinder 4.

 

My mileage is 161,000. I drove to the gas station today and it ran perfect. I think I may give the plugs a try. I have changed a few other vehicles plugs. Thanks for the help

 

As Pocketlint said, there are many different aftermarket coils available and quite a few people have said they had good luck with them. Just do your research before picking a brand. Most everyone would agree that sticking with the OEM plugs is the best bet for avoiding future issues. The Motorcraft part number should be SP479 and that interchanges with Ford part number AGSF22WM.

 

thanks for the help guys, I really appreciate it

 

Do you happen to know the part number for the coil pack? I think its the DG-508 but I am not positive

 

The one thing I will tell you is to get your self is one of these

https://www.amazon.com/GearWrench-80...rk+plug+socket

The spark plugs are down a ways in the cylinder, and this makes it a whole lot easier to get them out and it is on a swivel as well which makes it handy for the back ones. You dont necessarily have to buy it at Amazon, you can find them at most automotive stores ect.

It's nice to have when doing the job, because of the swivel and the length of it and of course the magnetic end helps the spark plug stay on it when your putting them in and taking them out.. Just a tip to help ya

If you dont know the Ford OEM part number you can just call your Ford dealer ask to speak to parts tell the guy your make, model year, engine and he will tell you what an OEM COP part number is for the COP and tell you what the COP's & plugs are cost wise and you can go from there

One thing to make sure you do before you change out your cops and plugs is try and get rid of any dirt, grit, dust etc from around the spark plug cylinders. If you have an air compressor you can blow around the cylinder areas, if you dont have an air compressor you can always use a shop vac and put the hose on the blower side and use that to blow and grime, dirt , or grit out of there before you pull any plugs out....If you do get some down a spark plug hole, just use a compressor or shop vac to blow it out of there

 

I think I am going to give this a shot at changing them out myself as I can buy everything for about 1/4 of the price of what the mechanic quoted me to do the work. The only thing I worry about is the plugs snapping off. I read where the plugs that Ford put in these model trucks are fragile. I assume these are the original plugs in this truck but I am not certain. I haven't had the truck long and it has 161,000 miles on it. Does anyone have any tips on how to get these plugs out and not snap them off? I know you can get the tool to remove them if the break off but I want to avoid that scenario if possible.

 

You can always shoot a little pentrant down each spark plug well and leave it sit for a little bit. When you go to take it out if it feels tight just work it back and forth by turning it to loosen it then as if you were tightening little by little, then try to start backing it out again.

Actually it was really the 5.4 3v engines that had a problem with the spark plugs breaking or coming apart in the well, doesnt really seem to happen much on the 5.4 2v engine. Honestly you really shouldn't have trouble taking them out, but as I said earlier shoot them with some pentrant.

What I did was I took my COP's off that evening and put some pentrant down each spark plug well and left it like that overnight so the pentrant could soak in and then in the morning went out and started to change them out, I didnt have any issues with my plugs. the ones at the back of the engine are a bit of a PITA but it just requires some patience, some extensions and the wobbly socket helped a lot in reaching them.

I would be really surprised if they were that stuck that you would need an extraction tool. If you come on a spark plug that is still tight, put some more pentrant in that well and let it soak and do the next spark plug over and then come back to the one that is tight later, but honestly I think you will be fine, just take your time and you ought to be fine

 

Still have hesitation in the motor occasionally after changing spark plugs and coils. There is also some sort of whistling noise that comes and goes from the engine and the coolant reservoir has a gasoline odor to it. When I drive the truck sometimes the temperature gauge will shoot up almost to the red but then it goes right back down. There is no white smoke or anything coming from the truck. Other than the little hesitation and the gas smell from the coolant reservoir, the truck runs decent. Could my head gasket be blown? If so how hard would it be to replace myself? I am not professional mechanic but I am mechanically inclined to some degree. I have replaced radiators and and engine manifold. Also the coolant in the reservoir looks a little brown like it could have oil or something mixed in with it, that's what makes me think head gasket issues.

 

honestly I have never seen a head gasket failure in one of these engines, when you took it to the shops did any of them perform a leak down test to see if you had a head gasket leak.

I know you mentioned the one shop said you needed a new engine but did they tell you how they came to that conclusion. I am sure there must be a kit you could buy to perform a test for a head gasket leak. I have seen them used on diesel engines to see if there is a head gasket leak, so I would have to assume that would work with gas engines as well. I am sure your could check at like auto zone or some auto parts place and ask if they have a kit

 

it is definitely acting strange for sure. I have never had a vehicle hiss when you remove the coolant cap either. So its whistling while driving every so often, the temp gauge shoots up and then goes right back to normal and it hesitates a little but there is no check engine light. the last code I got was a misfire in cylinder 4 but I replaced the plug and coil pack. I am almost positive there is something getting into the coolant because it smells like gas in the reservoir. I cant put my finger on it, it is acting strange. The manifold was just replaced in November of last year

 

I would think NAPA or some other auto place would have a head gasket leak tester

This is one of the Lisle ones on Amazon as an example
https://www.amazon.ca/Lisle-75500-Co.../dp/B0007ZDRUI

So you would be looking for something like this. Then it is a matter of testing and seeing the results. When you took the spark plug out of cylinder 5 did you look in the spark plug well? Was the well wet at all?

 

Thanks! the check engine light came back on and gave me the code p0304 for the misfire in cylinder 4. I haven't replaced the injector yet so i guess I will try that next. Another question is would a blown gasket cause cylinder misfire and if so why is there no smoke coming from the tailpipe?

 

I would think that if you had a leak that you would see smoke as well. I know that is teh case with the diesel trucks but I am unsure about gas. When you take that plug out of number 4 cylinder, have a look and see if you see any coolant in the spark plug well and have a look at the plug and see what it looks like