Engine Misfire in V8 mode

[BG1988]

SO i was driving and P0304 misfire cylinder #4 changed the spark plug and wire with a spare i had on hand,,

Maybe it's the COil pack? (have not tried swapping it yet)

intermittently running ok

 

[Dustin Jackson]

The cam could be worn or the AFM system isn’t working properly

 

[BG1988]

The cam could be worn or the AFM system isn’t working properly

it's making some mechanical noise( could be a bad pulley for all i know) not like Diesel Engine though... it runs fine for the first 30 seconds with no misfire i know the hybrid might have a delay when feeding it gas

besides that is only a minor fuel injector tick which has been since i bought it,

i'll pull the belt and do a compression test on #4 tomorrow


before it started missing firing the fuel trim was 2 to 4 range which is normal range.. so a vacuum leak can be ruled out on the 11th i did an oil change i didn't see any glitter..

 

[j91z28d1]

so many things can cause a miss fire in these trucks. everything from a lifter eating a cam, broken valve spring, coil, even an injector getting clogged or worst stuck open. could even be a loose spark plug itself, try snuggling it down. plug itself can be bad, crack you can't even see can cause random misfires.

ground wire to the coils is down really low near the motor mount. I hadn't even seen that one before till I needed to move wires around to change a mount.

 

[BG1988]

so many things can cause a miss fire in these trucks. everything from a lifter eating a cam, broken valve spring, coil, even an injector getting clogged or worst stuck open. could even be a loose spark plug itself, try snuggling it down. plug itself can be bad, crack you can't even see can cause random misfires.

ground wire to the coils is down really low near the motor mount. I hadn't even seen that one before till I needed to move wires around to change a mount.

heavy smell of gas out of the tail pipe

 

[Foggy]

heavy smell of gas out of the tail pipe

Better get it diagnosed and fixed before driving it.... You'll end up ruining your Catalytic Converters and that's real expensive !

 

[j91z28d1]

heavy smell of gas out of the tail pipe

usually rich smells like rotten eggs if the cats are working

 

[BG1988]

Better get it diagnosed and fixed before driving it.... You'll end up ruining your Catalytic Converters and that's real expensive !

Yes i know i'll disconnect the fuel injector for that cylinder :/

 

[BG1988]

so many things can cause a miss fire in these trucks. everything from a lifter eating a cam, broken valve spring, coil, even an injector getting clogged or worst stuck open. could even be a loose spark plug itself, try snuggling it down. plug itself can be bad, crack you can't even see can cause random misfires.

ground wire to the coils is down really low near the motor mount. I hadn't even seen that one before till I needed to move wires around to change a mount.

pulled the ignition coil swapped nothing changed tested the ignition coil we got spark. (just did a test from spark cable to a jumper cable to chassis ground)

most likely the AFM system broke

the fuel injector could be bad though


it runs fine for the first 30 seconds then starts shaking :/

 

[j91z28d1]

before you unplugged the injector, did the plug come out wet or more black then the others? that could mean the injector. and unless its tapping, I don't know that it's valve train.

did you do that compression test? I don't really know how you'd do that in a hybrid without maybe a tech 2 to engage the starter.

I would go to a auto parts store, buy one brand new acdelco plug and put it in there. that it runs smooth for a bit makes me thinks it's probably spark related still.