Tunes man, tunes. Stock I was getting 15.5mpg solo. Then I started modding things. Intake, exhaust, DP econo tune I was getting 17-17.5mpg. I picked up another 1mpg with big oil. Then things started to settle in and I could milk it to 20mpg on the freeway without thinking about it. Then I added B code injectors and it went to pot, down to 16-16.5mpg. I filled up today and I got 18.7 on this tank. The speedo was corrected for my 35" tires and it was all on the economy tune. And by the way, mine is an auto.