I've read alot of the past letters and they all seem to deal with gas mileage. I'm the same way as I check it every tank, but what did you really expect with 415 ci and a 6000 lb. truck? My '99 is a V-10 automatic 4x4 quad cab. It's a great truck but there is always ways to make it better. I've learned a lot about Ford fuel injection thru my supercharged '93 Mustang. The one thing I fail to see mentioned is a larger aftermarket mass air meter. Anyone make one? How about replumbing the intake and using a conical K&N airfilter? The superchip sounds good but the Mustang is taking my performance budget right now. For the record, I get about 10 mpg in town and 12-14 highway. If you're not using synthetic oil and the K&N you're wasting your time.