Just a question for any of the Chevy techs. I was getting an after market radio installed and the guy doing it did not unplug the battery when working on it. Well the harness he used was not the correct one in which the car electric system started going off and on. When I turn my car on now the gas gauge reads as full and when I stop it drops to empty the remaining part of the drive. When the gas level is low it drops and then goes up to a quarter tank and drops again. Is this something as simple as a fuse or is this possibly something bigger? Thanks in advance.