As noted previously, I carefully monitor the gas mileage on my car. Lately, the trend has been going down (from 32mpg to 30mpg to 28.5mpg to 25mpg). I am not sure what I did at the 25mpg fillup, but I did not think that I drove in the city that much.
My car is rated 26mpg for highway miles, which I drive at least 75% of the time. After seeing the 25mpg, I was wondering what I had been doing wrong. Can you guess what my next fillup gave me? A number I have never seen on my car. A number achieved by driving 55-65mph on the highway (depending on the speed limit, which I drive). That number: 35.7mpg, nearly 10mpg more than my car's rating and 3.5mpg higher than I have reached before. I had to do the calculation twice to make sure I was not introducing any errors.
Believe me, I will continue to drive at the speed limit to keep trying for these numbers. And I did it in a 1997 Dodge Stratus. Take that Toyota!