I must be getting old,lemme check, yup I'm old. I am actually happy with the power of my 2001 H. O engine but would like better milage than I'm currently getting. Its good but I'd like even better. Does anybody sell aftermarket performance equipment specifically aimed at improving mileage WITHOUT affecting reliability or durability? If it happens to also increase power I guess I can live with that too HEHE. As my daddy always said, power is like sex ,vacation and money. Enough really is'nt and too much is just right! Really though I am most interested in increasing mileage and as I kept my last truck for 21 years and plan to do the same with this one I really do not want durability to suffer.