My Pontiac 2000 won't stay running with the alternator plugged in. NEW alternator, plugs and wires, fuel pump, oil check switch, battery, It runs and drives normal when unplugged. I can't seem to fix it or find any answers. Is it the computer? What could it be. No lights came on and the dealership said it was the fuel pump, but it was replaced and the old one was only a year old and did the same thing. Runs for about 10 seconds and dies. Something seems to be shutting the fuel off?