Quits running often

Have vehicle scanned for codes. Possible fuel pump relay or pump getting hot and shutting down.

Does it just shut down quietly or does it buck, jump and quit? If the first the most likely suspect is the crankshaft sensor. They get heat sensitive and just stop working.

If it is the buck, jump and quit scenario, replace the O2 sensors. They get old and will stop working for a few seconds, that causes the computer to attempt corrections and then they start working again and the PCM now tries to undo the corrective measures and the cycle continues until the engine shuts down.

A quick and dirty check would be, if you have a tach in the dash, when the truck shuts down, if you try to start it immediately does the tach move? If not it is the crank sensor.