Sorry, this has taken so long. Gas mileage WAS 10 in mixed driving. It is NOW between 11.5 and 12 (and that is with some idle time for warming up in the below zero weather). The exhaust looks great and sounds good most of the time, except seems to drone on a bit on the highway if you accelerate at all (and of course with the weight and wind resistance of this thing - you have to push the gas a lot). I real have only put 150 miles or so on it - so may still be adjusting. Now I am trying to track down a water leak - but that is a whole other story.

 

Thanks for the update. Thats the exact same mileage ive been getting since my mods 11-12mpg every fill up. My mods are Airdoc, Flowmaster catback, and a Superchips programmer.

 

Any comments on a programmer for the 2008-2009 6.2 liter engine?