OK . Here's the car 94 Camaro LT1 A4
Here's the problem:
When the coolant gets over 200 F the engine goes insane. At idle it revs up randomly, surges in drive, and hesitates/misses when I get on the throttle. It drives perfect for the first 1/2 hour when its not totally hot yet. I also hooked up a scanner and sometimes the RPMs spike up to 5000 at idle but the engine is actually at 550 RPM.

Any ideas? I'm thinking optispark is the cause.

 

yup that sound like your opti is bad it sure did the same thing to me , one question for you though does your opti have a vent?

 

No, its the old unvented design, possibly never been replaced.

I'm going to try turning the fans on at a lower temp as a temporary fix. Its not my car, and the owner doesn't have the money to spend on a new optispark just yet.

 

check the coil wire first, just pull it off and clean it up, its dirty i bet, and the coil is a hella lot cheaper to replace than the opti