It's been almost a year and I have kept great records of all my fill ups. I have averaged 39.4 mpg since Mar 18, 2008. My best mileage was 54 mpg driving from Ruidoso, over the mountains to Albuquerque, where I used 2.5 gal for the trip. My worst was 33 mpg, which was the time my "check engine light" came on and it turned out to be a stuck emission valve.