betty_white

So i have a misfire cylinder 4 thats driving me absolutely crazy, I changed my plugs coil packs or ignition coils (which ever name yall call them) spliced into the wires and put a new connector on for the coil pack. I even held the coil pack up with the plug in it while my buddy started my truck to make sure it was firing. So then i put a new injector on and its still misfiring. Idk what else to do, my buddys neighbor works for a dealership so we went by his house and hooked my truck up to his snap on ultra scanner and it couldnt even tell me the problem. He thinks it might be the cylinder is getting to much air as in the intake manifold gasket may have a leak by that cylinder thats letiing in to much air. Has anyone heard of this happening before? I have had the intake manifold completely unbolted ready to come off then ended up having it back together before i got it off cause of an emergency, thats why what he said sounds logical but i want to hear other peoples input also.

rubbinsracin

I fought the same issue with CYL2 and changed everything just like you did. Sounds crazy, but try clearing the code, turn the key to off, then unhook the battery without starting the truck. leave it off for a night and put it back on in the morning. My truck never had a noticable problem other than it kept giving me the code. So I think by clearing the code, and not driving it and pulling the batter off it made the computer forget that there was a problem.

This is by no means a scientific way to fix the problem, but it eliminated my code and I have never had a problem since.

When you put the plugs and new COPs on, did you put dielectric grease in them to ensure good connection? A plug can still fire without it, but its a much cleaner fire with the stuff on there.

betty_white

No i didnt grease them, completely slipped my mind, im gonna try that when i get home today but its just crazy how this is turning out.

screamineagle

Have you performed a compression test?

techrep

iTrader: (1)

turn the key to off, then unhook the battery without starting the truck. ??? WTF His buddy's code reader will clear the code from the computer...

betty_white

I havent performed a compression test yet, thats what someone was just askin me this mornin at work. I need to do that cause this stutter taking off and at low rpm's is terrible. and yea my codes been cleaered several time battery and computer disconnected that aint doin nothin for me

rubbinsracin

I said it was a completely unscientific method. Maybe(most likely) it has nothing to do with it, but it worked for me. No need to jump peoples , Mark.

techrep

iTrader: (1)

No...that's no it....read what you wrote ?? it don't make sense.. (:

rubbinsracin

What about it does not make sense? Maybe I am a fool and not explaining myself correctly. I will break the steps out.

1. Turn key to ON position, clear code, disconnect tool.
2. Turn key to OFF position. Do not start the truck after code has been cleared.
3. Disconnect battery, leave overnight.
4. Reconnect Battery and go for a drive.

DISCLAIMER: This method is not scientific. In no way do I guarantee it will fix the problem. My thinking of disconnecting the battery immediately without starting is that if you leave it overnight it gives the computer time to, for lack of a better term and channeling my inner republican, unremember that there was a code there. I know that clearing the code with the scan tool should be enough, but again, I am just stating my similar problem was resolved by completing this exact step.

EcoBoostedF100

As someone mentioned do a compression check and also a leakdown.

I have seen a few where the compression showed ok but the misfire was from a broken valve spring. You did not mention how many miles on it?