Fuel gauge problem

[THudgens]

My gauge has recently gone bad and I wonder if anyone else has had this problem. The truck has 9000K on it and until 2 months ago the gauge needle would begin dropping after fill-up after about 30 miles. Now it doesn't start dropping until almost 200 miles, then it drops rapidly. As near as I can tell it is over a quarter off. My dealer has replaced the instrument cluster with no result. They have now ordered a new tank sending unit. I spoke with the mechanic and was told that he has had six Duramaxes come it with this problem, and this is a small Duramax dealer. He said that it appears as if the covering of the tank sending unit is being damaged by the fuel, or something in the fuel. Has anyone else heard of this?

[LarryM]

Shortly after passing the 36,000 "warranty over" mark, mine had the gauge needle stay full scale. The dealer wanted over 800 bux to replace sender unit, said they saw this before. I objected and started fueling by the trip meter instead.

After a couple fill-ups, the needle started dropping off the peg after a couple hundred miles. Then, after each fill-up, the gauge would respond a little better. After 10 or 12 fill-ups, the thing was back to normal and has not had a problem since. That happened about 30, 000 miles ago.

I don't have a clue what it's problem was.