What is causing my 2000 pontiac grand prix 3.8l engine to cut off? on 2000 Pontiac Grand Prix

My 2000 pontiac grand prix is cutting off on me sometimes it starts for a little while and other times just to fire it up you have to pump the gas pedal and keep your foot on it to get it to start and stay running and sometimes it just won't start at all. I have replaced the fuel pump fuel filter spark plugs.

Asked by for the 2000 Pontiac Grand Prix