"The engine/chassis combination is fabulous but is totally ruined by the program updates from Dearborn. After initial breakin I was getting 16 in town 21 highway.After each dealer service my mileage decreased until it is now 9/13. The power initially was amazing; I could pull a house. Now I can hardly climb hills. Last dealer visit, a factory rep said get a new 6.7L the factory had no plans to fix the problems with the program downloads for the 6.4L. Sounds like the 6L fiasco all over. So I'm selling and looking elsewhere. Love the truck! Hate what the factory did to it and me!"