My 2014 EcoBoost with 3.31's gets an honest 2 mpg more in the city than an identical 2012 EcoBoost I had with 3.55's....
Mine's also a 2014 EcoBoost Crew Cab 4X4 with the 3.31 gears.
Going to Colorado 2 months ago, I got 19 mpg all the way to Colorado Spings, and 21 mpg all the way back to Texas. I kept the cruise on 75 mph both ways, and it's 670 miles each way.
With the 36 gallon gas tank, I didn't have to fill up until Pueblo, CO, going up there.
Coming home, I topped off the fuel in Colorado Springs before I left, and I still had probably 3 or 4 gallons left in my tank, when I got back to Texas
And with the low torque of the EcoBoost, it really ate up the hills like they were nothing going up Raton Pass! Love my EcoBoost.
