Here's something from the inexplicable files:

On a 600-mile trip from TN to NC, noticed the fuel indicator never left the FULL mark. Even ran out. (No worries, I have a bed-mounted auxilary tank.) Eventually took it to the Ford Dealer, who found that the float was wedged behind the rest of the assembly--kind of like how it gets shipped from the factory--thus preventing it from giving an accurate reading. The mechanic told me that this could only be purposefully/manually accomplished (by removing the tank and putting the float where it was.)
Disregarding saboteurs intent on making me run out of fuel, does anyone have an alternate explanation?
I was pulling stumps (rather forcefully), and I believe that the motion of the diesel in the tank (about 3/4 full) may have caused this. Sherlock Holmes said this was impossible.

 

Mine did the same thing after a couple of hard launches in 4wd at the track. Got there with a half tank left with a full tank! Have yet to drop the tank, but I suspect I'll find something similar.

 

I had the same thing happen after fueling up, twice. Both times the float dislodged itself after a while.