Well I thought I should post and give a little bit of hope to other 6.4L owners. My super-duty now has 212k+ miles and I just got back from an almost 1400 mile trip from Las Cruces, NM to Fort Collins, Co. and back to Cruces. I was able to achieve 20+ mpg with 3 passengers including myself, luggage and a light load.
An observation I made was that driving habits really do matter, and before anyone assumes I am being sexist be aware that I said driving habits! from the three of us driving, there was one girl. We had the best mileage out of the guys driving, the funniest part was that she (the girl) wanted to look for the cheapest diesel through the trip
and when we first filled up when she was driving I told her we need diesel, it was so funny when she replied "This truck is diesel?!"
Thank God I was awake when we stopped at the gas station to fill, my great performing truck could have been destroyed if she had put gasoline in the tank
I Like her, shes a great friend, but 300 mi into the trip I thought she would have known it was Diesel
and a quick note: the girl was the one with the driving habits that gave us the worst mileage. we were lucky to see 20 mpg when she was driving, as well as being a passing lane driver, could not figure out the space rocket buttons on the dash
oh man, I like that girl, she looked so cute when she would swerve to turn on the wipers or the headlights.
I want to put a leveling kit or a lift on the truck to at least customize it a little more than just a headache rack and a tool box that I have on her, but I really like the great fuel mileage it's giving me on these long trips I've been taking lately
Another thing I noticed was the large smile my friends got on their face when the truck will pass vehicle with ease and drove through the Colorado snow smoothly. And my friends decided that my truck be named Sno-white, they fell in love with my truck
If God permits I will like to see Sno-white get to the 300k mile mark!