I am new to this forum so first off a have a 97 grand prix. It runs fine...for awhile when it gets warm sometimes it spits and sputters than when i park and shut it off it doesn't start so i checked the fuel pump relay and changed it. it started it idled fine but when you press on the gas it spits and sputters and the tac jumps bad, i unplugged the mass air flow senser and it run smooth I changed the mass air low senser and changed the fuel pump but it still does it but not as often i keep monitoring it with my obd2 scanner but only code that it troughs are the mass air flow and the second o2 senser.I have asked other auto techs and there not sure ether what is wrong