Thread: misfire problems

tune up coils, icm, those are the first stings to check.

move plug 1 to 3, then the plug wire, swap two coils around. your looking to make the misfire move. last ditch effort is the injector swap around. then the icm to get tested at a parts store.


unless your just long over due for a tune, just do that.

ignition control module. its what the coils are bolted to.

swap the injector then, check over your wires to the #1 injector.

bad pcm dont normally cause just a misfire.

and a injector wont cause a compression problem. think bad valve or f ed up piston.

damn and your a v8, missed that part. same rules apply tho. move stuff till the misfire moves with it.

If you have low compression, it's a possible DoD cylinder.

Displacement on demand, same as active fuel management.

The LS4 has DoD and switches to 4 cylinders while at normal cruising speeds. The cylinders that shut down are known to burn oil and even sometimes lose compresssion. The other biggest failure if have the lifter sticked closed or ruin the camshaft.

Did the mechanic perform a compression check or was this a guess.

That's where I'd start hell rent one from autozone and do it myself

If you're even guessing the mechanic's work...I'd suggest finding a new one or learn from doing it yourself. At least you know it's getting done right even if it might take you longer since you've never done it before.