Okay, I've been trying to track down this misfire forever.

Plugs and wires have been changed btw.

I've narrowed it down to it only happening when the engine bay is absolutely heat soaked. It's doing it HORRIBLY today, and it's 85 degrees outside. The car runs PERFECT at night when it's cooler.

And it doesn't happen if the coolant temp is high by itself, like if it's been idling on a cool day in traffic. The whole bay has to be hot as hell. It's so bad I can barely drive the car today.

Any ideas? I'm not sure where to start looking on this one.

 

Please post the year built and any other mods.

Possibly the ICM is bad as it is heat sensitive.

 

1994 Trans Am GT, 25th Anni. A4, 3.23 posi.

Cat back exhaust, straight pipes with bullet muffler
Air foil
LT4KM
Descreened MAF

I've heard about the ICM from someone else, as well as the cooling mod for it, does this help alot of people? I've never heard of this problem with the ICMs until I told this problem to a few people knowledgable in Fbodys. Is this common?

 

I had the same problem, it was the icm. Do the icm mod on shoebox and you'll be golden.