1997 sunfire (pontiac) wont start

I bought it off my friend and he told me it stopped running after he filled the tank up with gas so his mechanic said it was the fuel pump i bought it off him bought the fuel pump and installed it and it still wont run…itll start for a couple seconds then die…

There might be a problem with the ignition module. Ignition modules operate in two modes. These are the start and run modes. During the start mode, the module allows full battery voltage to the coils. This insures a cold engine starts. Once the engine starts and the ignition switch goes to the run mode, the module goes to the run mode. It’s here where the module drops the voltage to the coils so the coils, plug wires, and sparkplugs don’t burn up.

So if the engine fires up as it’s cranked over, but stalls out as soon as the ignition goes to the run position, the run mode of the ignition module my have failed.