...pontiac grand am? i have changed fuel pressure regulator valve, throttle switch, gas cap, coolant temp sensor, and have put 3 used fuel pumps on. also changed the relay switch. i can put gas in the throttle body and it will start. runs great after that all day. but if i drive it to work and let it set until i get off, it won't start again. does any one have any idea what else could be the problem?