2001 Chevy z71 starts but doesn't run need help diagnosing problem

[brownkid72]

I have a 2001 Z71 with a 5.3L and last night I was going to the gas station and I started my pick up and it ran no problem for a couple of seconds, and then it started sputtering like it was running out of fuel. Walked to the gas station got two gallons of fuel, and tried starting it and it would start run fine for a couple of seconds and then start running rough then die. I then put two more gallons of fuel in the tank and tried again, same scenario would happen. I at checked to see if I had fuel at the engine and it did.

When I put fuel in it the first time I heard the pump start up when key was turned on engine off, and every time the key was on and shut off when it was at pressure ( I assume) I was unable to check fuel pressure where I was at last night.

My question is what could be causing this issue of not running?