Thanks. I appreciate itI'm guessing here but a majority of the time your sending unit will go bad....it just happens.
I'm not familiar with your car but the sending unit is in the fuel tank. On my 5th gen the tank sending unit and fuel pump are accessed from under the back seat. If you remove the unit a simple ohm meter test on the lead will tell you if the sender is bad. If it checks out good then it's probably the gauge. Those rarely go bad. Search "how to test a fuel sending unit" and you'll get 6 billion + hits.
Good Luck. let us know what you find please.