So I got this 1988 GTA 5.7 and I cant figure out whats wrong with it.
About a week ago I got check engine light flashing randomly while driving, car started to bog down. So I found that my spark plug wires had to be replaced due to cuts. After replacing the wires, plugs cap and rotor car ran fine for couple of days. Today I had an issue with code 51 and flashing check engine light while driving on the freeway (at 105F outside), It started to slightly misfire and check engine light started to blink. I Removed ECM and reseated the Prom chip, also applied dialectic grease to the connectors, but the problem is still there. When car is hot (+200F to 210F) it start to misfire with code 51.
I think I need new ECM or new Prom. But my question is: Would ICM failure cause code 51? And what vendor sells good ECM and Prom replacement if I end up needing them. Thank you.

 

So I end up replacing ICM since I had one laying around. I went for a drive, same conditions, hot day, loads of traffic. Issue seems to be resolved, but since its intermittent I'm not 100% convinced. Still wondering if code 51 is something that ICM can trigger or its strictly related to the car computer issue.
Thanks.

 

I guess Ill update this thread on my progress, in case anyone else have the same issue. Code 51 was for my faulty ECU, i took it out and tapped on it, saw my check engine light come up and car started to run rough when I was tapping on the ecu, swapped prom chip with the borrowed chip from other car, same issue, swapped ecu but used my prom chip and the car started to run like a champ. In conclusion, I have bad ECU. Damn I guess this forum dying, not a single reply.