The problem keeps repeating itself

I have a 92 Buick LeSabre 3.8L, and I have had nothing but problems with it since I bought it. When it decides to run it runs great. Hopefully someone might have an idea what could be wrong. When driving down the highway, it'll just stall and never start again. So far I replaced the fuel pump, fuel filter, starter, alt., battery, ignition module, crank poss. sensor, plugs, water pump. The last time I had it in, the mechanic did some rewiring between the crank poss sensor and the ignition module, and it ran like a champ, until about a week ago when it died going 55mph. This is the 3rd time it has done this after a mechanic worked on it. Please help. Thank you.

It started out to where it would stall out on me and start right back up. Then it got worse with time, and would half to wait a few minutes to a few hours and the then it would start back up, to waiting days before it'll start up When it started doing that, it would run for a few seconds to 10-15 minutes then stall again. It wouldn't sputter, or hesitate, it just stalled and that was all she wrote.

I had an 89 that did the same thing. The only trouble codes I ever got indicated that there was problems with the transmission speed sensor assy.and cam sensor* (which I replaced*) I finally gave up and sold it for parts when it became flat out dangerous to drive. It had 205K on it and was not worth putting a lot more money in. Seems common on these cars. Perhaps someone here who is a GM tech could advise further.