i have a 2013 f150 with the 3.5 ecoboost engine and i am getting horrible gas mileage I am getting 10 city and 18 highway , now i do only drive 5 miles one way to work everyday in the city but i recently went on a 300 mile trip to northern michigan and i was only getting 18 mpg at 55 mph and 16 at 70 mph . I drove 70 mph on e the way up and 55 on the way back to see if there was an optimal speed so it was 600 miles round trip . Does this sound right ? I spoke with someone who said i should take it back into the dealer and have them reprogram the ecoboost engine , has anyone heard of this? what is every one getting mpg wise?