The first thing I did was re-calibrate for the tire difference, ford tech did it in minutes, they have a 35 inch tire to choose from...It was nice to not have to get a programmer like back in the day...
I had the truck for 500 miles maybe before the lift/tires i was seeing 17-18, but the motor has to break in, so im sure that would have gone up.
There is no need to re-gear, like i had thought I might have to, the truck has tons of power, and its basically like a 3.55 now...
My dealer cant believe Im only getting 12-13 mpg either, but i am...
I haul a 2 place jet ski trailer 5 days a week for 5 miles a day...other than that the truck is a creampuff...I drive normal, I dont drive it like a race car. and my mpg history is 12.4 after 3500 miles.
And I run 93 premium...
Actually, that's all quite believable to me. And I could be wrong but, I suspect the drag induced by the lift-kit itself, depending on how the lift was accomplished, combined with the extra weight and size of your tires, are all contributing to fuel economy that isn't all that different from a Raptor. The Ecoboost is only going to return the high numbers you had in the beginning on a stock truck. While you obviously didn't build a wide-body Raptor, it sounds like you added quite a bit of load to the truck.
Here's what I'm thinking...A Raptor sits only a couple inches higher than a stock F-150 4x4 and is rolling 4.10 gears instead of 3.73s found on most of the FX4 and other 4wd f-150s. One inch of that "lift" is the tires alone. The other inch is a slightly higher ride height from the springs and geometry of the front control arms as well as the springs out back. The front skid plate provides some protection but, it also was designed to fit flush with the bumper and direct a healthy amount of air around what would otherwise be a drag inducing crossmember up front.
Conversely, my understanding of the Rancho 4-inch kit is that it bolts in using the stock lower control arm mounts. I've seen this kit and to me, it seems a lotlike hanging the landing gear out from under a plane...It creates a lot of drag that just burns even more fuel at highway speeds. Depending on the width, height, and weight of your wheels, combined with the lift and final drive ratio, it seems to me you could readily create enough extra load on the powertrain that you might as well be hauling a payload of 1000lbs or more in the truck. At least that's what I'm thinking. The fact you're getting 6.2L Raptor mileage would almost seem to support my theory.
