2003 gmc 2500, vortec 6.0L, 115k miles, had a 1/4 tank of gas at time of incident

Went to the circus yesterday and when we left my truck started acting up. When I gave it gas it would fall flat on its face. And I heard some popping/backfiring sounds as well. I had to drive the truck home giving it the least amount of pedal input as possible because anymore than that it would just basically shut down on me. I was just glad to be able to limp it home. Last yr I did a full tune up plugs, wires, air filter, fuel filter, cleaned intake because it was stalling out when I would come to stops or turn into parking spots going very slow. that problem is fixed, this one is definately something else. Im leaning towards fuel pump? Going to rent the tool and check PSI tomorrow but what do you guys think? Ever hear of a truck acting up like this before. The auctozone guy said it sounded like it was getting TOO much gas. So would that be something else then other than the pump? please help