I know there have been a lot of driveabilty posts lately, hopefully someone has run into this. Went to the dragstrip last night, 100 miles, the car missed very faintly a couple times.(93 Z28 6m) Made my pass, then when I got my timeslip, the car would barely run. Chugging, bucking, popping and carrying on. Now it wasn't a faint miss. I let it sit, then decided to head home. Fired up fine, crisp throttle reponse. I let it idle while airing up the tires, then the exhaust note changed, same deal. It was a trick to get it moving, it wouldn't rev up, had to lunge forward. Ran crappy till I hit 4 lane. The temp went from 95 to 80 outside. The rest of the trip it didn't miss a beat. All day today it wouldn't duplicate the problem, I let it sit with the AC blowing and it just wouldn't. I don't trust it. I realize it may be fuel, or ignition, but I can't tell. Every thing checked out fine today. My question is can the ICM freak out when hot but still work, barely?

Btw I know opti is the 1st response, but I replaced it and the fuel pump 5000 miles ago, last year, the water pump is not leaking. Anyway thanks for reading this far.

 

Yes, the ICM can heat soak. Shoebox has the fix:

http://shbox.com/1/4th_gen_tech2.html#ICM_cooling

The optical sensor in the Opti could also overheat.