Truck stalling.... leave it over night next day starts right up??

If battery gauge in going down then test the alternator and battery terminals & terminal wires and connections points.

If have your alternator tested it sounds like something is breaking down once hot, most likely the voltage regulator. A lot of auto parts stores will test it free of charge but you usually have to take it of your engine and take it in, luckily yours should be on top of the engine. I hope this helps

If there is rust or other contamination in the tank it could be sucked up against the fuel pickup screen and cut off the flow. Take away the suction and the stuff settles and the fuel flow can start again. I don't know but this is a possibility.