The only thing I have ever seen that seems to work pretty consistently is using a cotton gause, performance air filter. Before I added one the best I ever got was 25mpg once with an even driving mixture, when I dropped in my K&N I immediately got 27 mpg and was able to hit a peak of 29. I think one thing that can make a difference is where you get your gas from. The best results I have received have been from Texaco (which unfortunately is no longer available in this area), Gateway F/S, and Mobil. I have had lousy results with Casey's, Murphy USA, and Citgo (which I never go to unless an emergency). Have any of you found a difference.