You have a problem in the fuel pump relay circuit for sure then. I'm betting the relay, but it could be that dropping resistor.
THE FUEL PUMPS ARE LOCATED IN THE TANKS THEMSELVES. I JUST WENT THROUGH A TRACE AND LOCATED ISSUE THAT AT FIRST LED ME TO BELIEVE I HAD LOST A FUEL PUMP. WHAT IS THE ILLNESS ON YOUR TRUCK?
probaly a fuel pump its common for vehicles to do that the best thing to do next is a fuel pressure check to verifiy its the pump
The wires should be grey, orange and black, purple, and a black wire. The purple goes to purple, grey to gray. The orange and black goes to the small black wire on your car harness and the black goes to the bigger black.