Hello and welcome to JA. As long as the gauge is correct, then a common
problem on the truck is that the evap. system vent solenoid is stuck, causing backpressure in the tank, causing the pump to shut off. That solenoid is above the spare tire, has a large plastic hose going to it, and 1 electrical connector. sometimes tappinh on it will help, if not, needs to be replaced. If this was helpfull, please ACCEPT. Positive feedback also welcome, thanks.