I'm having issues with my 1985 Camaro, 2.8L injected. The check engine light flickers both when I turn the key on and when the engine is running. I jumped the 12 pin connector and got a code 51 (PROM fault). I can clear the code by disconnecting the battery and then run the car with no issues, but when I turn it off and wait a minute, the problem re-appears all over again.

This issue is intermittent. I will act up for a few days, then go away for a few days and come back. I can't figure out why. Any ideas? I replaced the ECM a few years back, only to have this happen again. (I don't know what codes were present back then).

Can I resolve this by replacing the ECM (I don't know the part number, I haven't looked that far) or is there a secondary problem that could be causing this? Seems to me if it is intermittent, there could be a secondary cause, no? Is it possible that I replaced a faulty ECM with another faulty ECM?

Thanks in advance for any help!