Sounds like you have a loose connection. On mine the ground wire had just about come off. It was only hanging on by a few strands and was giving me problems. Check the connections on top of the fuel tank and the harness. There's a green or white plug(can't remember the color and I'm a few thousand miles away from my truck), right beside the tank in the wheelwell. Pull the plug apart and see if there is any corrosion or moisture in it. Hope you get it figured out.
