It's worse than that. The 6.9 IDI is probably the worst engine ever put in a truck. So all of them got horribly abused, and killed off early. The only possible thing that could be more dumb would be to put that same engine in a truck with 2 fuel tanks, an ambiguous fuel tank selector switch, and a cowl mounted fuel separator running on the suction side of a mechanical fuel pump made out of aluminum with a rubber plug that cannot withstand corrosion by...water.
This is the only possible configuration that will allow the engine to suck air, lose prime, die on the road...and miraculously seal enough to not leak diesel. Fortunately, it only happens after servicing the truck and pulling the water separator pull ring. So if you never maintain your truck, it lasts longer. But you do have some interesting discussions with your service advisor. Similar to the 5.0 Coyote typewriter tick, and associated rod bearing failure. "Well it ran fine before I changed the oil..."
Now if you put a turbo on that 6.9 and call it a 7.3 then it starts to get better. As long as you don't put it in front of an E4OD...