Fuel Gauge

I own a 1999 Alero and am having fuel gauge issues. After I fill up, the gauge seems to work properly until it reaches almost to 1/4 tank and then it goes "wacky", it gradually and slowly goes back to the full mark. When the tank gets close to empty the fuel light comes on and the gauge drops to "E" but momentarily and then flies back up to "F". I was wondering if anyone else is experiencing this type of problem? I am using the "Trip" meter after I fill up. Thanks for any response.
Randy

You probably have a bad fuel level sending unit. It's located internally in the fuel tank as part of the fuel pump module.

I have a 99 with the same problem change out the floater. youll be fine afterward.