I was driving on the highway last weekend and i was forced to drive on the shoulder or get crushed by a truck that didnt see me. When i pulled onto the shoulder i ran over a shredded tire. I didnt think much of it at the time, but when i looked down at my fuel gauge a few hours later i noticed that it had went from showing a half of a tank to almost full. The gauge itself is not physically broken because it still moves up and down when i turn the car in and off. Also it goes down at the correct rate, its just at the wrong position. I filled up the other day and the needle was at full, and so far i have driven 100 miles and its still at full. Any ideas on what it could be? Thanks!