I have put on 1600kms on my ecoboost and have been monitoring my milage with the on board computer and comparing to real world numbers. My computer numbers are accurate to the fuel used verses actual fill up quanities so far. Keep in mind my driving habits are conservative and I have been using cruize control on the highway runs when not in stop and go traffic on the 401. My communte to work is 70kms one way. I have a backflip cover as well which helps a bit. I had my truck weighed full of fuel and myself and it came out at 5940lbs.

110kms I average 9.3L per 100kms = 30MPG (imp) = 25 mpg (US)

115kms I average 9.7L per 100kms = 29mpg imp = 24mpg US

120kms I average 11.3 per 100kms = 25mpg imp = 20mpg US

130kms I average 11.6 per 100kms = 24mpg imp = 20 mpg US

Overall ave for 1600 kms so far is 12L per 100 = 23mpg imp = 19 mpg US.

I am using the same gas pump, pumping at the same speed and stopping when the nozzel clicks off. I am within a half a liter at most as compared to the computer usage.

If you were to drive aggresively the numbers would go down quickly.

Cheers