Bad fuel gauge?

Lately I've noticed it takes a few more gallons of fuel to fill my tank than usual. I normally only need about 26 gallons to fill up when the gauge is at
about 1/8th of a tank. The last few fills required 30 gallons or more. I didn't think too much of it until yesterday. I ran out of fuel on the highway pulling a trailer with just under 1/8th of a tank. Luckily, I was close enough to home to call my wife and have her rescue me with a can of diesel and my tool box. What a pain in the ass to get started again after you run a diesel dry. It takes much longer to bleed the air out of the system than it does after a fuel filter change. I ran out only three miles from where I planed to stop for fuel. After adding almost all of a 5 gallon can of fuel to the tank (some was dumped into the mostly empty filter canister, some dumped on myself) it took 29.7 gallons to finish filling up. I have a 34 gallon tank on my '99 2500 QC SB so now I'm convinced the gauge is reading too high. Anyone have any ideas why the fuel gauge is reading higher than it should? Does the sending unit have resistance values that I can verify with a meter? -- Ken
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looks like it's sucked up. I've ran across this a couple of times and it acts just like you said. If the tank is flat then you probably have a sending unit acting up.
Denny
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Denny wrote:

The tank looks normal right now, but it does have 34 gallons of fuel in it. I'll have to check it when it gets low again. -- Ken
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The sending units do go bad. On my 96 I am on my 3rd one. My experience is that as the sending unit starts to fail the gauge reads low.
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I had the same problem in my 95 3500. left me on the road a few times before i changed the sending unit. good luck. Andy

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