Inaccurate Fuel Gauge?

[Shaneliberty]

I have a 2002 F-250 7.3L that I have owned for a month. At first, I thought I was getting below average milage out of a tank of diesel. Then I did a trip to mexico and a few longer around town trips and noticed the economy was doubled based on my trip and the fuel gauge movement. Well, one of the times I filled up after noticing the gauge dropping pretty quick, I found that even though I was near 1/8th of a tank (I know it's better to fill up at 1/4) I only ended up putting 19 gallons in the tank before it was completely topped off. After that fill up, I noticed that the fuel needle would change where it stopped randomly after turning the truck on.

My question. Is the sending unit faulty? I have a 29 gallon tank and with the data I have, I am getting about 18mpg average and the gas gauge is just plain wrong. Anyone have issues with an inaccurate gas gauge?

[alabamafrog]

Haven’t had any trouble with my gauge but here is a link to my fuel system mad pics, if you drop the tank anyway I highly recommend spending the $30 or so and doing this stuff. Shutterfly | View Shared Pictures

[06pwrstrokerbullitt]

Well I have an 02 powerstroke with a 29 gallon tank and I thought my gauge was reading fine until I ran out of diesel with the gauge reading just under 1/4 a tank. I was thinking man this thing has ran on a 1/4 tank for a couple days now but I guess I was just using fuel and not moving the gauge. I had ran lower on diesel previously even until the low fuel light came on but for some reason I ran out so now I always get some diesel before 1/4 a tank.

[gwgnc]

I had a 99 that did the same thing. I thought I had fuel in the truck because it was reading a 1/4 of a tank and all of sudden the low fuel light came on and I didnt make it 2 miles to gas station. So I carried truck to the dealership and they told me my speedometer cluster was bad and needed to be rebuilt. After that was done everything was fine

[Shaneliberty]

I already replaced the fuel filter on the truck as well as the air filter. My reasoning here is the amount of gas I end up putting back into the tank versus how low the gauge claims the tank is. There is no way there is another 10 gallons at the 1/8 tank mark.