Ok. I have a 1989 Iroc-z with the 350 TPI. All Stock.

While I am driving the car the check engine light comes on and stays on. When this happens the car will idle really high but still drives good. I can reset the computer and everything returns to normal operation but when the light comes back on I cannot get the computer to flash any codes, not even code 12 will flash. When I reset the computer code 12 will flash.

Any help would be appreciated!
Thanks

 

Sounds like maybe your ECM is going off in the weeds for some reason. (Maybe going bad.) May be loosing a ground or power for a short time Make sure your grounds at the rear of the heads are all clean and tight. Disconnect clean and reconnect both battery connections. While the battery is disconnected, it may help to pull and re-plug your ECM connectors back on. Might not hurt to wire in a voltmeter to your battery to see if the voltage is doing something out of the ordinary. I have done this and routed the wires inside the car and put the meter in where I could see it all the time. Also a bad, intermittent battery can make electronic stuff do some mighty weird things. Good luck and keep us posted

 

What exactly are you doing to 'reset' the computer?