Problems with my 1992 Olds 88

I’ve already taken my car in twice for the same problem, and its still not fixed. The problem started with the car seeming to have problems going up hills. Then one day it just died in traffic. I tried starting it up again, it would turn over but wouldn’t run. I had to wait about fifteen minutes before it would start running again. When it got going it only went three miles before it died again. When I got it to the shop they claimed it was a bad battery. They hooked it up to the computer and said it wasn’t the electronics. When I got the car back it ran for a while, then started stuttering again (turn off then within a second start up again as I was driving down the road). I got it back to the shop, and they finally decided it was the fuel pump and weak hoses. When I got it back the second time, it seemed to work okay for three weeks. It then died again. This time, however, I was able to start it up immediately after coasting to a stop; and I was able to travel eight miles without it dying again. When it dies, all the lights on the dash come on and the car completely shuts down. The muffler/exhaust seems to be making a rumbling sound. Could this be the problem? The car has approx. 95K miles on it.