Have a 96 z28 that stumbles/hesitates/backfires at 3500RPM when I give throttle. Doesn't matter if its WOT or half, when it gets to 3500RPM is just loses all power until I let completely off. Also the car dies every so often just when sitting in park and idling but always starts right back up. Sounds like two things to me, ICM or Opti. Any ideas?

 

Check Fuel Pressure.

 

do you have a coolant leak?

 

for the idle, check the IAC valve for crude and buildup. for the falling flat on your face at 3500, fuel pressure, then maybe the coil before assuming opti

 

Was a weak fuel pump. Problem got worse and ended up finding out the pump would drop pressure then build back up then lose pressure again. Replaced pump and car runs great.

 

Check you fuel pressure, coil, icm, and the Opti connector. After everything checks out check the opti.

 

I've had it happen to me before.. Hence why I said fuel..


Then again the Opti will go out if you look at it funny..

 

Crap my opti just went out.

 

If that's your face I'd worry about more than an Opti..

Face like that will get you in good with the bearded lady at the carnival.