I need the Mazda guys and gals to help me out a bit (or anyone else for that matter); Last Friday I drove to work like every other day and I had a half of a tank of gas left when I turned the car off in the parking lot. It was 6:00 am and around 55° outside. The car sat all day and when I left the air temp was about 80° and it was sunny. When I started the car the gas gauge read 2/3 of a tank. I somehow had more gas in my tank according to my gas gauge. I assumed my gauge was failing but I filled up today with a third of a tank left and somehow I achieved 51.23 mpg - far above the norm. I made sure the tank was completely filled using the same gas pump I always use. I normally get around 42 mpg with my 2007 Mazda3 Touring 5sp using moderate hypermiling techniques. Besides someone secretly putting gas in my tank during work hours, how is this possible? Has anyone else experienced anything like this? I work with a bunch of engineers and they have no good theories at all.