I have a 89 formula Firebird with a 5.7 v8 engine. When I try to start the car sometimes it starts and runs fine but sometimes the service engine soon light will flash a code 12 and the cooling fans will run nonstop plus the IAC valve cycles. At times if you sit and wait for it to stop the car will start and drive fine for a while but it will eventually die and the cycle starts all over again. Sometimes you can push on the E-Prom and it will stop this cycle and the car will then start but of course die while being driven. We have replaced the E-Prom but it hasn't solved the problem. We also have tried a new ECM but no luck. I'd appreciate any help.