There is a few things here and there that the guys on the site can recommend to help get a few more mpg out of it get a signature together to see what you have done on the truck to see what suggestions might help you the cummins motor is very detuned from factory for warranty and emiss.awsome truck ya gotThanks for the welcomes the only neg about the truck is fuel mileage, but then who buys one of these for mileage! I definitely love the exhaust brake hauling that toy hauler, wow these things are built for towing.