Car: 98 420a powered turbo dodge avenger.

Problem: while I was sitting in traffic the car out of no where started idling really rough, egts dropped substantially, and was very hard to get moving. (running on 3 cylinders instead of 4.

Diagnosis: Well I started with spark. Figuring a bad coil, fouled plug or burned up wires. Replaced the plug with one from another cylinder and put a known good plug from that cylinder into the misfiring 4th cylinder. Nothing changed. Swapped my friends coil pack off his 99 eclipse gs (flat pin just like mine). didnt change a thing. swapped out the wires as well and still to no avail, the misfire only occurs in 4. I tried the cranking the car with plug attached to the wire on the coil while resting on the manifold to see if it would spark and it did not. could the wiring harness to the coil be bad? bad PCM? Im getting frustrated. I figure if it was a compression issue I would have multiple misfires.

Trace the wiring back from the coil pack. If you have the EGR sill installed on your engine sometimes the wires can rest against the EGR pipe and melt causing a short.

Originally posted by djtrickee
Trace the wiring back from the coil pack. If you have the EGR sill installed on your engine sometimes the wires can rest against the EGR pipe and melt causing a short.

Thanks for the quick reply. EGR is removed and blocked off. I just traced the wires back from the coil and I see no signs of damage. Any other suggestions?

You still might want to check your compression. Your rings could be fudged up.

Originally posted by Yo
You still might want to check your compression. Your rings could be fudged up.

If I didn't have compression I would get multiple misfires, instead of just the 4th cylinder. Correct me if I'm wrong.

you could have local damage on just cyl #4 is what's meant. Check your wire maybe just broken inside. If the coil was bad you'd loose another cyldinder fire also since it's wasted spark. I'm brain-fartin right now on which one it is...

No compression

1: 50psi 2: 100psi 3: 100psi 4: 20psi

Royally screwed. New motor purchase at the worst time possible.

Replaced coil with MSD unit, new MSD wires and new ngk -1 plugs. Car runs smoothly now, but im going to do another compression test to make sure all problems are corrected.

I have been having cylinder misfire too. My engine started running really rich for some reason and I started getting mis fires. I checked the plugs and the New NGK were already covered in black and running really bad. It only took about an hour for them to Mess up.
Upgradecar.blogspot.com Its the first page.

easy to worst. compression, each cylinder with in 10% of each other, check plugs wires and coil, then from there is goes sensors like crank and cam and then rings head gasket or pistons...AKA bad news...