Oldsmobile/Buick Repair: car randomly stops, fuel pressure gage, olds alero

Question
I have a 00 olds alero gls with a 3.4l engine. This august I replaced the motor (my intake gaskets were leaking and I drove it home from school anyway). Recently the car feels like it wants to cut off. When I went to visit my brother 6hrs away the car just stopped, it cut off, deaccelerated.  It started right back up. On the way home it started acting up again but it was worse; you could only drive for about 15min then the car would stop; you would have to wait 20-30min before it would start. When I got back I took it to the place where the motor was put in and got a oil change and he put the service engine soon light out and said it was a evp code and it could possibly be a map sensor. Since then I have replaced the gas cap and put some heet because other people were tellin me it could be some bad gas. After that it stalled on me again and I took it to midas for a diagnostic and they said it was the fuel pump. When I went to let my mechanic put the fuel pump on they said I didn't need a fuel pump just use some heet.  Now the car has stopped on me again when I was driving from school I took it to a dealership  and they didn't have enough time to let the car continue to run to get a full diagnostic. Help I don't want to drive a car that just randomly stops.

Answer
Hi
I would have your mechanic check it until it stalls. Have them drive it with a fuel pressure gage attached until it stalls. It REALLY sounds to me more like fuel pump than any other item. USUALLY, bad gas will also make the vehicle run VERY poorly, missing, sputtering, etc... other symptoms besides an intermintant stall.
Have them check other items that could create this concern.... plugs, plug wires, coils, ignition module, power and grounds to the PCM module, ignition switch.....there are ALOT of other items that it could be, but I really would suspect the pump AT THIS POINT. Have them check it out.
Thats my advice.
I Hope it helps
Good Luck
PAwl