Yes, my 6.4L got 8-9 towing (my trailer/my driving style), 10-11mpg plowing and idling around town all winter, 12-14 empty/mix city driving, and 16-17 open highway (average). These are all on-par with my 6.2L. My 6.4 had been dealership owned it's entire life, was used as a car hauler and had 100k on it when I bought it. When I got it, with 100k of all highway miles (avg speed was like 54mph, truck had stupid low hours on it, 1700 I think) , hauling 50% an empty car hauler (open) and 50% with a loaded car hauler, it showed 13.5mpg (if I remember correctly) on the MPG readout, which I promptly re-set.