Why the gas gauge go pass full or stay there
It may be your float in your gas tank. If it is sticking that would be the first thing I would look at. However, you may not have to replace it, it may just need to be cleaned. There could also be a problem with the fuel gauge sender. It’s important to know how much gas you have available, so I would recommend having this checked sooner rather than later so that you don’t get stuck without gas on the road.