I heard everyone bragging about EcoBoost gas mileage so I thought I had to try one. My last highway trip (about 1000 miles) averaged 13.7mpg. I have the 3.31 rear end which I thought would get better gas mileage...now I'm wondering if the low ratio rear end might be better. (maybe 3.73) Now I'm hearing from the same ones who were bragging about such great mileage, that its not quite as good as they first thought.  The truck drives great and has lots of power, but when I put it under any type of load the mileage really goes to pot.  Just wondering if others are having better luck?