I try to put diesel in my truck every time it gets to 70 miles to empty I started at 50 to empty and it started studdering on me so I moved it to 70 if I get 68 it starts studdering. Could it be some water in diesel and if so where do I drain it. Got to change oil in 2000 miles gonna change fuel filters

 

Don't rely on the LIEOMETER, my sister found out the hard way her truck runs out of fuel with 100 to go, each truck is different, I don't have a lieometer but I can run to a full needle below empty, not recommended though because it will pick up the stuff you want to leave on the bottom of the tank/KRUDD/
The water drain is on the side of the frame mounted fuel pump on the drivers side of the trans, you will need a 6mm allenwrench to get the plug out, do yourself a big favor and get the replacement plug that is made out of Brass and has a **** so ou don't need any tools as the stock one will rust and can get stuck in there, ou can find them on Ebay and some dealers carry them, you don't want the steel one you want the brass one..

 

It's probably just running out of fuel and the lie-o-meter is doing it's job of lying to you. My buddy had an 05 that had a mind of it's own. Ran out at 40 miles to empty at it's lowest and 110 miles to empty on it's highest.

 

Thanks guys will check on brass drain screw also

 

The P/N for the brass plug (both International and Ford) are listed in the fuel filter change sticky at the top of the 6.0 page bud.