Didnt read that did ya? Ive had one too but in a rc/lb superduty and it got 11-13 but mostly closer to 11. Put some 17x10s and 33x12.5s on the superduty and it was ten or a hair.better.
Ive had three vehicles.with that motor, my dad keeps impeccable fuel mileage records, and 15 aint happening on a 5.4.
Lemme.guess, you're driving habits get you 20 in that 6.4? LOL
LOL so I guess your experiences trump others? LOL Plenty of people get better than 15 MPG, you need to come out from under that little rock of yours and open your eyes to the real world. I'm not saying the 5.4L can get 20 MPG, but 15 MPG is easily attainable. I also like how you changed the number from 14 to 15... I never previously stated anything about getting 15 MPG.
5.4L in a Super Duty vs. a 5.4L in an F-150 is a huge difference in fuel mileage.
I have actually achieved, on occasion, a hare over 20 MPG in the 6.4L at 60-65 MPH. It's on stock tires and suspension. That's been done countless times on tuned/deleted (otherwise stock) trucks. Vivian is claiming mid-20's with her tunes.
Like I said, it all depends on your driving habits. Just because your dad is a grandpa doesn't mean he drives his vehicle in a fuel efficient manner. And just because your experiences differ from mine, doesn't make my (and many other owners') experiences incorrect.
Just made a 2400 mile round trip in the wifes new 2013 FX4 Ecoboost and let's just say I have yet to drive an off the show room floor diesel that I liked better.
I have built/modified many a diesel truck from the Dino 7.3 to 85,000.00 2013 6.7's and none have driven or handled like the new F150/Ecoboost trucks, for a light duty trailer hauler/daily driver they are/will be hard to beat.
Average mileage was 18.1 driving north of 80 every Chance I got, only drawback is the truck wants to cruise at 90 so speeding tickets may offset any savings in the average .50 cents difference in fuel cost, just saying.
18.1 MPG at 90 MPH.... Impressive, to say the least. My Super Duty would get around 14 MPG or less at those kind of speeds.