Hope this helps.
I piggybacked off your forum since I had low mileage 91 chevy stalling problems also. Mine was more dramatic, going within two weeks from sometimes stalling at lights (but idle was fine as long as I threw it into neutral), to starting to stall at 65mph on the freeway. After testing/changing out everything imaginable, it was finally decided to change out the ECM. Fortunately you can get them fairly cheap (reconditioned), but they are not the easiest to get to to replace. It has been running fine for the past week.