Wife was driving the truck(I was the passenger) while towing our dump trailer. After approx 100 miles into this trip the dash showed a "Reduced Engine Power Warning", and then shuddered. That was immediately followed by a "Service Engine Soon" warning on the dash, and the truck shut down as we were pulling to the shoulder. I smelled diesel fuel as we slowed to a stop. I got out and saw some smoke coming from under the hood. I looked under the truck and saw burning material falling from underneath, I shouted fire, and my wife exited while I retrieved our dog from the back seat. The cab was filling with smoke. Wife called [XXX] while I retrieved a few more small items from back seat. We stepped back and the truck was fully engulfed in flames in a few minutes. Fire crews were on scene after several more minutes, and by that time the truck was burnt to the ground. This truck was in excellent condition with no prior running issues or warnings of mechanical problems. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)