my truck starts starving for diesel when the gauge goes under 1/4 of the tank. when the tank gets filled up(which hardly happens now) the gauge goes way past full could it be the gauge?

 

I I fill very slowly toward the end of a fillup, I can get a few extra liters in there and it can cause the gauge to read 1/4 past full, so I think that part is notmal. The problem of stalling at 1/4 to empty however, is not normal. You most likely have a broken fuel pickup line in the tank. I've read there is also a return line with a rubber valve at the fuel sender that can cause fuel to enter from higher up on the fuel sender and produce similar symptoms. Either way, you are likely looking at dropping the tank fo find the problem.

Whats the most you ever put in the tank by the time it starts starving for fuel?

 

I agree with David85.

Just to clarify, even though this is not normal, it is very common. Mine does the same thing on the rear tank.