Thanks for the replies. It sounds like I am not going to find the ECM schematic. I am a electronic technician by trade and really wanted to fix the ECM myself.

I have the ECM out of the case and will try to trace back to the UART. Also will look for any cold solder joints that someone else pointed out.

I was lucky to have a 1993 engine and auto trans setup in my garage waiting for a future hot rod conversion. Used the 1993 ECM and traded Proms with my 1992 6spd and have been running ever since.