Re: gas gauge problem?
Ther is a device called a sending unit which sits on top of the tank. It has a float and is connected to the guage on the dash by two wires. Yours is bad. Locate the sending unit, it may be under an access plate. On mine (120 gallons)there is a tank manufacturer's data plate next to the sending unit. Mine had the model of the tank, capacity and phone number of the manufacturer. I called them and got the factory specified replacement. If you can't find that, there are generic sending units. Follow the directions. I preferred the factory recommended replacement as I wanted to be sure of it's accuracy.