The old fuel filter had 23000 miles on it. The terrain we travel is the same as we traveled last year. I was dang impressed with the throttle response when first programmed and it actually is getting better fuel mileage when empty. The only two things I can think of is 1-fuel filter and 2-the programmer. Am I mistaken or are the programmers supposed to help with fuel milage as well as power? thanks for your input and help!