Why do a 1990 Chevy Lumina and Grand Prix, with the same engine, stall?

Both cars have the same engine, the Chevy Lumina is mine, the Grand Prix is owned by a friend of mine. The Lumina just had most of the sensors replaced (crank, throttle position, etc.) and has been doing this for quite a while. Both cars will start and run fine if you take out the fuse for the computer for a few minutes and put it back, but as soon as you give it gas, it starts acting up again and cannot go more than 15-20 MPH. The Grand Prix started acting like this about a month ago and is now about as bad as the Lumina. Any ideas?
Why do a 1990 Chevy Lumina and Grand Prix, with the same engine, stall?
Its a Chevy. Need I say more?
Why do a 1990 Chevy Lumina and Grand Prix, with the same engine, stall?
sounds like a weak fuel pump