Thread resurrect:
I had an '84 Buick Century with the 4- cylinder engine. Upon installation of a President George with a TX-800 behind it, the ECM promptly died, rendering the engine inoperable. Went through the entire installation from front to back, bought a new chip, keyed the radio and it (the ECM) died again. After that I bought a third chip (did I mention these things were $100 a pop?) and learned to run a barefoot radio.
However I really wanted to run that TX-800 so I sold the Buick, bought a Plymouth and installed the same setup. Never had any problems with the Plymouth.