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Discussion Starter · #1 ·
My fuel gauge has started being very erratic. It was reading empty when I had half a tank, then it read full at half a tank and slowly came down to half a tank. I shook the truck when it read empty and that seemed to fix it. It's acting normal now but am I looking at electric or the actual sending unit. I have looked around a bit and if it was the sending unit it should be reading empty right? I don't think it got hung up as it was at half a tank and parked on level ground.
 

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The sending unit usually hangs up at the top (I've had it happen with a less than full tank after a 4WD launch at the strip).

If the wiring is not making good connection, it will show full with an open circuit, and empty if shorted. IIRC, the sending unit resistance is 15 ohms empty and 160 ohms full.

If you check the wiring and the resistance of the sending unit, and they check out, then it may be the instrument cluster. You can check that by getting two resistors and using them at the sending unit plug to simulate the sending unit.

You could also drop the tank and physically check the sending unit, which I'd probably suspect before the instrument cluster.
 

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Discussion Starter · #3 ·
I am going to see if I can get by with an inspection camera. Otherwise I will drop the tank. I did just pressure wash the underside of the truck because it was coated in oil about a 1/16 inch thick fro. The front of the transmission to the rear of the truck. Maybe I got water in a connector?
 
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