Beretta.net

...Also check the ECM's ground. Basically, when your car is cold, the ECM can ground itself through the O2 sensor. Once it switches over to closed loop mode (when it gets warm), that ground becomes unreliable, and the car will not run correctly if at all if the ECM's ground to the engine and/or chassis has become compromised. Run an Ohm check on the ECM case when it is hot and stalling-out. Or, just run a jumper-wire to the ECM case from a good ground, and see if that fixes anything. Remember though, that the ground has to be to the engine too, not just the chassis, so if the grounding strap from the body to the engine is gone or bad, you might need to run that jumper-wire all the way to the block, and make sure it is a good sized wire too (14 gauge should do it, test purposes at least).

So far as 'reflashing' an '89 ECM... Wow. That is OBDII stuff, like '96+. Yeah, someone either has no clue, or just hopes you don't.

Does your car have the digital instruments? That can make it more difficult if it does, since the ECM actually runs so much if the digital cluster...

Just an update - I decided to change the ICM first. So far, no problems (knock on wood). Thanks for responding...