The fuel indicator, and travel computer is cheating me in my towncar

[Ar/t]

Hi, maybe, all you can help me,
in my towncar '91, the fuel indicator is damaged or somethig, cause when i load gas, the indicador says that i have more gas that is real, and the travel computer is up and down,,,
when i turn of the car and turn on again it show me less gas,,, is very imprecise,,, can someone tellme what is the problem?

and again,,, sorry for my bad english,,, jeje

 

[Frat-man-du]

Could be the float in the tank (part of the pump assembly is sticking) or you have a bad ground wire in the circuit.

 

[Ar/t]

what can i do, in both cases? where is that gorund?,,,