check fuses first but I dont think that is what it is. My DD had the same thing happen to the temp gauge after I jump started it one day except it was reading that it was too hot and it wasnt. It could be the actual in tank sensor or maybe you have a hole in your tank.
in the fuel tank i believe, near the fuel filter. you can get to it under the rear seat cushion, but idk exactly how to replace it. dealer did mine under warranty and it was smelling like a gas station for days.
they did, i came back and complained, and they detailed the car for free i was like wtf, i opened the cushion and found a big spill that soaked into the sound proofing material there and part of the seat.