Some things to check:
The wiring. The connector at the tank is a possible problem spot.
The constant voltage regulator in the instrument cluster is another possible cause.
A loose or disconnected ground wire can also be a problem. There are several under the dash, and one at the gas tank. There is also one under each kick panel on either side of the car.
If everything checks out OK, then it is most likely the gauge sender. This is located inside the gas tank, and requires removal of the tank to service it. It is normally sold as an assembly which includes the gauge sender and fuel pump. Some of the aftermarket places do sell the gauge sender by itself.
Good luck!
Wednesday, September 25th, 2019 AT 2:38 PM
(Merged)