Hey guys, I just had a local alarm shop install a viper alarm in my 2011 mustang gt 5.0. When I went to pick it up I started the vehicle and the gas tank gauge showed empty and the info reading said I had 0 miles before empty. I swear when I dropped it off it had just over a 1/4 tank left. Anyways, I first suspected that they went for a joy ride. When I went to chevron to fill up however, it only let me fill a little over 8 gallons. When I started the car again the tank read full. I believe this car holds about 16 gallons. I called the alarm shop to ask if they had to unhook the battery during installation and they said no. Anyways, I thought it was weird that the gauge read empty and then full after only filling up 8 gallons. It sounds like the gauge reading was incorrect for some reason. I can't figure out what happened. Any ideas? Thanks.