Need some help.

I have put about 10,000 pretty hard miles on this truck since October when i bought it. it has 167,000 on it. It has pulled like a champ and complained very little

It has a misfire, and I pulled P0300, P0302, and P0307. I did all spark plugs and COP boots yesterday. Glad to report that i didn't break any, but seems like an overly involved job for spark plugs. But I am a 7.3 guy.



The misfire issue however, was not solved.

I also found that the Cylinder 2 well had about 1 inch of oil in it. Not sure how to handle this. When i found it, I thought that would be the reason for the miss in Cylinder 2. I guess not. The CEL has not come back on yet. I have to drive it today, so hopefully that goes well and it survives.



Here is a video of the truck idling after the spark plugs.

https://photos.smugmug.com/Hosted/i-..._2185-1280.mp4

I'd really appreciate any help you can offer.

Fuel Filter next? Other ideas?

I really need the truck running as it is my work truck. It has not thrown the check engine light yet, but I will post back if it does.

 

New coils would probably do the trick.

If $$$ is a concern buy a couple instead of 10 and swap until miss is corrected.

I however prefer to replace all 10 so I can be sure things are right during troubleshooting.

than again it could be injector connectors cracked or a bad cylinder or two. IE low compression.

 

OHM the COP's they should be no more than 1.1 OHM's

 

Thanks guys.

I ended up finding a mechanic that could work on it yesterday.

He found 3 bad coils and the heater actuator valve leaking coolant in that glow plug well. It wasn't oil.

We think bad gas may have brought all of this to life so i am trying to run the rest of the gas out and I'll keep you posted. It still has an intermittent miss, but is leagues better than it was.

 

 

It's a 3-valve, not a 2-valve (it has an aluminum valve cover in the picture).

The ohms on a coil will be different depending on which you check

Primary is low (1.1 ohms?) and secondary is high (tip of coil to ground conductor on the hold-down).

 

I wouldn't worry too much about the miss. I've still not solved a miss on a few of mine, and as need dictates, the truck is used. Pulled 5000 to 7000lbs without issue while coding three misfires. I've got connector issues on mine. :/

Luckily I only use the truck once a month or so for short trips.

 

The way I have tested the coils has been thru the pins on the COP. and yes a bad coil with an impedance of 1.1 OHM or more is a sure sign that its bad, same concept goes when testing the Glow plugs on a diesel truck. A good working COP should read .9-1.0 ohm. If you get a good OHM reading make sure the boot is not damaged, the coil spring inside the boot is not sticking out the boot when on the COP, make sure its not a cracked COP or bad wiring causing the missfire.

 

Sorry for not updating everyone.

I took the truck to a mechanic that day. I rely on this truck daily to carry my tools and haul whatever. Ranch work. They ended up replacing three coils, and the heater valve which was what was leaking coolant into the #2 Spark Plug well. $700 later..... It is still missing.

I think there is some chance all of this is being caused by bad gas. It started immediately after a fill up. However, I have put about 30 gallons through it and Lucas injector cleaner and it has improved.

I sounds like a Motorcycle when i take off then smooths out as i go. Above 2000 RPM is hardly misses at all. It seems to combust much better when hot and running, but at idle and taking off its obnoxious.

It occasionally throws P0300 (random misfire) and even less often throws P0303.

I have researched everything, PCV, Injectors, Spark Plugs, coils, boots, etc and nothing seems to match.

I tried to change my fuel filter today with an oil change and air filter but broke the blue clip off the line going to the engine. Now what? It still runs without leaking fuel, but i can't change the darn filter now.

I am about at my wits end with this. Although it is working fine for me, but the last thing i need is another huge repair bill.

 

 

I would say 99%, all the ones I tested that were bad always gave a reading of 1.1 or more the good ones always tested between .8-1.0 OHM (anything below .7 i would not know ive never tested one that read below .8) and theres those COP with cracked housings that give good reading but the damaged housing causes them to arch and cause a missfire also the ones with corroded pins give you infanite ohms.

 

Just an update.

I still have not solved the issue.

Most recently, I installed a new injector in cylinder #3. No luck.

I also changed the fuel filter. I just Picked out the blue ring and O'Reilly had clips that fit the adapter on the fuel filter so that I could put it back together.

The fuel coming out of the filter was muddy. I thought for sure that would resolve the issue, but nope...

It still misses on multiple cylinders at idle and low rpms... below 2300. The longer it idles, the worse it gets. It runs almost perfectly after going down a long hill in gear. And it has no issues at cruising speed even if accelerating unless lugging below 2000 rpm.

Makes me sad because i love this truck, but i wish i could figure it out. May try the PCV hose next.... Shot in the dark.... I may try to move the #3 coil to #1 and glance at the spark plug again. Maybe removing all anti-seize from the spark plugs? Any ideas greatly appreciated!

 

If it were me.....

I would....

Put a new maf in it
Put a new fuel pressure regulator in it
Put a new temp sensor in it..
Put a new IAC on it
Check all vacuum hoses and replace bad ones
I also put new O2 sensors in my new purchases
Take throttle body off and clean it
check operating voltage....if below 13.5VDC fix because low voltage will affect fuel pump.
have all 10 injectors ultrasonically cleaned

if exhaust manifolds have broken bolts repair them. An exhaust leak will affect fuel delivery due to poor o2 sensor readings.

 

Seriously, you don't need to throw parts at it. A new MAF? Really? I have yet to see one personally go bad in my or any of my acquaintances' vehicles. Same goes for the fuel pressure regulator. Unless a simple diagnosis says it's bad, there's no need to throw money at it.

(Simple diagnosis: Hook up a fuel pressure gauge. At idle, should be 28-30PSI - disconnect the vacuum to it, it should jump to 38-40).

Back to the OP: You should get some kind of scanner that can read the misfire counters and see if there are particular cylinders misfiring, or it's totally random. The fact that it runs good after going downhill for a while, in gear, sounds like maybe the EVAP system is full of gas. Do you smell gas at all?

 

Yup, really

I also would replace all coils with new.

looking at condition of plugs and plug wells, I suspect even more needs replaced to make truck dependable.

like...

tps, and or throttle body motor, and knock sensor.

OP asked for suggestions.
I tend to want things new so dependability is not an issue.