IRONFIST

Alright so...
A month ago I rev'ed up my stock LS1 a little too high, bent a few pushrods...
Fixed that, but ever since then there's been a misfire on CYL 5. Now it is getting spark, but if I unplug the injector at idle.... there is no reduction in idle.. the car runs the same.
If I do that with every other cylinder there is a noticeable decrease in idle.
If I rev the engine up a bit you can't hear/feel the misfire anymore. The car also seems to pull pretty good...

Anyways, so I popped the valve covers again, and nothing unusual, valve springs seem ok. I'd really like to track this down before I do my head swap...

Ideas?

BaddBird

iTrader: (6)

Just because your getting spark doesnt mean your getting enough spark. Easy way to find out. Check #5 with a kv tester if you dont have one swap #3 coil with #5 see if your misfire moves.This can also be done with the injectors. You could also have a bad plug.

shaun

this might sound wierd but i had a 98 grand prix gtp and i had a few boltons like sc pullys, cai and my bro drove it and hit the rev limiter and it cooked one of the wires and the stupid thing is they where new wires and the car was perfect before that.

try just swaping the wire around some thimes it some thing so small and stupid and we spend a good amount of time trying to find it.

dewey04

iTrader: (7)

Is the missfire constant? Hows the compression on that side of the motor? if it's good swap coils from a good cylinder, then wires, then plugs. If still nothing make sure your getting 12v at that injector and try swapping injectors.

IRONFIST

Compression seems ok, I'll try swappin around plugs/coils first...
If that doesn't work I'll try injectors.
And if that doesn't work I'm not sure what to do...
And yes it has a consistent miss...
You can actually hear it pretty good in the morning air...