For those that might be having fuel starvation problems, while using the left side tank, consider this. It is possible for the tank selector switch contacts,... related to the gas gauge, to be good, and provide an accurate reading. But, at the same time, the contacts, within the switch, used for providing 12 volts to the selector valve, on the frame, ..be bad.. I had this situation recently, using a half full left tank, and an empty right side tank. I thought I'd diagnosed the problem correctly, replaced the fuel pump, and everything seemed fine. However, shortly, I broke down on the road again. This time I eliminated the valve, and bypassed it with a piece of gas hose, .....and got the truck home. Since, a normal valve will "click" when energized, ...with the ignition on, ... I gently touched the dash switch, while positioned for the left tank. I could have used it as a telegraph key, click, click, click. I'll be replacing the switch, and also installing a pilot light, powered by the 12 volts, at the solenoid, ... when the left tank is being used. That's my story, and I'm sticking with it.