Truck stalls when hot and will die until rpms are below 1000

Hello, sounds like a fuel or air control issue. The mixture is definitely in question; you could be getting too much fuel for the engine to handle without a proper air mixture (depressing the accelerator to the floor often will disrupt fuel supply on a fuel injected vehicle). Either way, testing of the fuel delivery system and the air intake to check for any vacuum leaks, air intake leaks, or air flow restrictions is the best starting point.