[Boudy]

I'm not thinking that you have a gauge problem. It goes to zero when the key is turned off. That tells me that the gauge itself is not stuck and is responding properly to voltage levels issued to it.

Let me get the lowdown on the gauge itself and I can help you trouble shoot it better.

The overall steps, though, will be to feed the gauge with the various voltages to fully test its range.

Then, run the same test from the tank side. This will test the gauge with and without the wiring harness of the car.

At that point, if the connections at the tank are good, the sender is stuck and needs to be replaced. At which point I would tap on the tank with a rubber mallet to try and free it prior to dropping the tank.

Boudy