1999 ford mustang coup gas gauge stuck on full

1999 ford mustang coup gas gauge stuck on full. Just bought the car, it was a known condition been this way 2 years. any ideas?

Ah, if only the gas TANK were always full. Wouldn’t that be great?

When the gas tank is almost empty, take a rubber mallet and bang on the bottom of the gas tank. If the gauge reads lower the float in the gas tank is hanging up.


I had this problem on a 1998 Ford Windstar. The fuel sending unit wasn’t working. It wasn’t the float being hung-up, it was a faulty wiring harness, which was replaced with a used one from a parts yard, which did the trick.

Sounds like you either have a short in the wiring system or the float in the tank is hung on something holding it in the full position all the time.