I hope it helps your mileage too. That is the reason I did mine, but they they were all well within specs (except for one). I don't know what else to do. I've tried everything I can think of, but I can't seem to get my mileage to consistetly stay above 14.5 mpg. I know you are pretty much in the same boat and I feel for you. A few extra mpgs goes a really long way.