I just purchased a used 1997 GP. It's the best car I've ever owned in my life, but it has some quirks. One is the fuel gauge is stuck on full and no one can seem to fix it, which means I am constantly watching my odometer to determine whether my car needs gas. Periodically the gauge drops down to about 1/2 full then zips right back up again. So far, no one can seem to fix it.
Any suggestions?
Thanks.

that is one of the modifications that Pontiac has been working on in the newer GTP's so my suggestion is have the system replaced or at least have your gas lines and the tank inspected.