Slim Chance, one thing you might consider is your truck is brand new! When I bought my 2010, it kept getting better gas mileage for an amazing long time. But, I was always burning ethanol free. Sandawilliams, his truck is new, and has a 5.7, I am not certain what year yours is but I would think the 6.4 would have even a more pronounced difference in mileage than our 5.7's and hopefully if yours is older, then his, they have been making improvements on burning ethanol! My 97 Dakota REALLY did not like Ethanol!, the check engine light would come on if I continued to burn it, and the plugs would not last as long, as well as getting worse mileage. The 2010 doesn't complain with check engine lights, (when i can't find ethanol free), but certainly mine loses power and mileage burning it. (doesn't help its lifted and on 35's)