get your truck's diesel pump and automizers checked. I had exactly the same problem with my diesel engine. As soon as the car warmed up it stalled on me like it had it's fuel supply cut off. I let it sit for a while and it would run fine for some time then did the same thing again. I had the automizers replaced and the the plunger inside the diesel pump was replaced. My car is running like new again. hope this helps solve your problem.