I had the same thing on three different trucks. 1 the pick up from the top of the tank had a pin hole in the steel line from rust out.Looked ok till I pulled it.The gas level went low and the pump lost it suction. 2 Some jerk stuck a piece of heater hose over the pick up on the and redirected upward, to avoid sucking up dirt or the water in the tank. the hose got gooie and collapsed. 3 The petcock on the bottom of a tank got full of rust over time and got sturred and partially blocked the bulkhead hole. I also had someone jammed a fuel filter on top of another in a Ford fuel pump and when the engine need maximum amount fuel, the engine would stumble.Most of these issues were from trucks that all sat for years and people just pushed into service without going thru the whole truck first
