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I'm new to this forum but love watching scannerdanner videos. I just watched one of his videos about testing a fuel gauge sending unit on a GMC. In the video the problem with the vehicle was the gas gauge was always on E. So for starters names Phil. I own a 1998 GMC k1500 with 125,455 miles on it. The gas gauge fluctuates from F to 1/2 tank after driving 100 miles or so. After watching the video I saw earlier I think I might know what it is but my fuel gauge doesn't stay on F or E. It just moves all around the place. Could my situation be the same ?? Faulty fuel pump sending unit ??? Or is mine a different problem all together. I suspect it's the sending unit after watching the video and obviously I'm gonna do my Diagnostics before condemning the sending unit but I'd love some input.. maybe someone on here had the same problem and fixed it.
Your are on the right track.
All these sending units work much the same way, basically a potentiometer, much like the volume control on an old style TV or Radio or on a car the throttle position sensor works much the same way.
That the gauge only starts to read wrong when the tank contents go below a certain level would make me think it is a fault with the tank sender unit inside the tank.
Just thank you luck stars that you don't have european car some of them have two sender units on one tank.
" We're trying to plug a hole in the universe, what are you doing ?. "
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Moved your topic to the repair section.