Engine mis-fire problem

[jmbrooks]

Hey group,

My car: 2000 Camaro 3.8L A4 89K miles

The other day I started having a mis-fire problem. Took it to Autozone to pull "check engine" light code. Cylinder #5 mis-fire. Suspecting the coil pack, I swapped the first 2 coil packs. If the coil pack is bad the problem would move to cylinder 6. Test drove the car and it ran fine. Drove it later and it was mis-firing badly again. It did not set a code but the check engine light flashed some during hard acceleration.

The guy at Autozone (for what it's worth) thought if the coil pack was bad it would affect 2 cylinders, in this case #2 and #5 as they are on the same pack. He also suggested the injector as a posibility.

Today I pulled the first 2 coil packs again and checked them with a meter. post to post was about 15.8K ohm (both) and open from the spade slot to the corresponding post. No help there. Put em back in (still swapped from thier original position). Took the car out and it ran fine, except for one time mis-fire during a hard acceleration. It was a long drive even on the highway.

I'm still suspecting the coil pack as that is the only thing I have messed with trying to diagnose this. The plugs are fairly new platinums and the wires are 6 m/o MSD's. The first and third coil packs may be original, they still have the cylinder #'s on them, but the middle one may have been replaced as there are no #'s. The middle one is for cylinder 2 and 5. You guys got any ideas??

Thanks
Russ

[Meatyshells]

Re: Engine mis-fire problem

how old are your o2 sensors? They can go bad, so they some times read lean when theres nothing wrong and then add a bunch of fuel causing a misfire. And they dont always throw a code.

[jmbrooks]

Re: Engine mis-fire problem

I've only had the car for just under a year, my guess is that they are original.

My line of logic is this; the car runs fine after i have been messing with the coils.

2nd drive today and it is still running fine. Read some posts about wires being damaged by heat. I have the 8.5 MSD Superconductors and checked the ones on the drivers side (cylinder #5 is on the drivers side closest to the fire wall). They look as new as the day I put them on.

Russ

[ava1219]

Re: Engine mis-fire problem

that sounds like what my car did before. heavy acceleration my ses light would blink. but found out the spark plugs just needed to be replaced and also got a tune up.

[ava1219]

Re: Engine mis-fire problem

my ses light would blink and misfire*

[OneEightSeven]

Re: Engine mis-fire problem

If you throw another misfire and OBD-II tells you which cylinder it is pull off the boot (wire) from the output on the coil pack handling that cylinder. Take off just the one boot for the single cylinder's wire, not both boots from the coil pack (each pack handles 2). Start up the car with that single boot off and see if there is a consistent spark coming from the exposed lead from the coil pack. It should ground itself on the block as it fires. If you see a lack of spark you have a bad coil pack. Take the boot off another cylinder's coil pack if you want to see what it looks like when working properly.

If you remember which coil pack you moved and which part of the coil pack was handling cyl 5 (stock coil packs are numbered) you can pull it off now and see how it's performing if you can't manage to throw a specific code.