fuel gage on 1998 Chevrolet Cavalier

My fuel gage sticks in the full position until a lot of gas is used and then it drops down to about 1/4 tank. I'm not overfilling it.

Asked by for the 1998 Chevrolet Cavalier
Commonly this is a problem with the sending unit in the tank, BUT, have a tech scan the sender just to make sure before you authorize any parts to be replaced.