Truck wont start after it has been running and engine is warm

Sounds like you have a leak in your high pressure oil system. The fuel injectors on these engines are operated by using high pressure oil. If this oil pressure is low the vehicle will not start. As for it only starting hot this is due to when the oil is cold it is thicker and wont seep past the failed component but when hot and the oil is thinned-out it can now seep past the failed component causing low HPO in the system and not firing the injectors. This model is know for the rail plugs or dummy plugs that are screwed into the oil rails on top of the injectors to tear, and deteriorate causing this issue. I've seen this happen as as early as 50K. Another know area for HPO leaks is at the STC (snap together connection) fitting located on your high pressure oil pump. Over time it can blow off which can also bend the branch tube (a connection pipe which transfers oil to both cyl oil rails). In some extreme cases it can blow off with such force it hits the rear cover cracking it. This causes a no start condition and a external oil leak in the back of the engine! Their is an updated fitting that has been fixing this issue. In some cases if the branch tube has been bent too much it wont line up with the pump any more. Bending it back into place posses it's own problems and in some cases can be done others it cannot and replacement is necessary. These repairs can be expensive. So be aware other issue might arise after further inspection has been done. Hope this helps. Good luck!