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Q: Gas gauge doesn't work correctly and moves randomly registering wrong amount of gas

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Hello, I'm having troubles with my 2001 Sierra that has around 85,000 miles. The gas gauge seems to be working fine but sometimes it just starts registering wrong gas amount. Although I filled the gas tank, it indicates that it is empty. Then it works normally and shows the correct amount. But, occasionally it moves to full, if I am going downhill. This occurs while I shift from drive to neutral. It generally takes correct position when I shift to neutral. Other times it just moves randomly. When I took it to a mechanic, he said I have a worn-out fuel pump. It would be pretty expensive to replace as it is located in the gas tank. Do you have any ideas how to fix this thing?

Yes, the fuel sending unit is part of the fuel pump module. If there is an open in the fuel sending unit this will can you the false readings you are experiencing. The tank will have to be dropped to complete this repair. You may want to enlist the help of a mechanic, such as one from YourMechanic, who can safely drain and drop the tank and replace the fuel pump assembly.

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