92 Riviera randomly stalls

Did you get the wires on the icm pushed all the way down its in a tight place if I remember, This sounds more like a loose connection than a short although a 26 year old car probably deserves to have an intermittent short. I'm still betting on a connection.

The stalling and no start happened before the icm was replaced, but i will double check the connection to be sure. thanks.

The correlation between the check engine light and the no starts is whats getting me.

I just remembered this old test, it's called a tap test, get to the ECM I think it's behind the glove box or under the right side of the dash or kick panel turn ignition on until the lite fails to come on use a rubber hammer or something similar then rap on the ECM as you watch the lite if it blinks flashes or comes on replace ECM. It's been a long time, let me know

Tapping the ECU didn't seem to do anything. After a few key turns the engine light did turn on so I tried to pull codes. Got through the first set of 12's and it just stopped flashing. Seams connection to the ECU is being lost somewhere.

Your right, you can perform a test called a pinout where you test each wire on the ECU separately, The sad news is that if it's working when you test it all the wires will test good. No way around it as far as I know, maybe someone else on this site have other ideas luck,