What was done to the engines to reduce the mileage? What model years are best for mileage? and what are the most cost effective( cheapest) upgrades to improve mileage?

 

i drove a pumped up '03 that had the 250 hp motor, it was w/o a doubt the fastest diesel I test drove. AND it had a problem with the motor that was pointed out to me when I had it checked out... (it had an extra rattle that shouldnt have been there). the more hp you get, the more fuel you'll use. that is most likely a big part of the milage drop. someone will add to that I'm sure.

I have an Edge with Attitude for my main performance boost. it rocks! between that and the AFE Stage 2 kit it has tons of added torque & hp. cost effective? i'd do an intake & exhaust to start...

 

nail, hammer. . . you get the picture

now the best thing I have done to get my mileage to where it is is to use Power Service and MMO. my BHAF, gutted intake, MAP mod havent come close to the mileage gains.