One day i came of the store and my truck would turn over but its like it wasnt getting any gas. i poored gas into the intake and it would run off that gas for a couple seconds and then quit. I had someone bang on the gas tank and it started and ran fine. I decided it was probably the fuel pump. That was about 2 months ago. Yesterday I had the same problem but i could hear the fuel pump working. I put gas in the intake a few times and it would run off that for a little bit. Eventually it started and ran fine. I am lost on what it might be. Maybe the fuel injectors or a sensor?

 

Maybe try a fuel filter. Banging on the tank and it starts working leads to to believe the pump may have a problem. Just because it's running don't mean it's necessarily pumping. I would measure the pressure to make sure you really have proper pressure. Good luck.

 

Fuel pressure guage will tell you a lot. On start up, idle, rev, wot. Instead of guessing check those first my friend.