i left my tires at factory pressure which seems to be very overinflated
12.4 mpg in streets on my 2017 supercrew at 11k mi (when i bought it initially used)
recently it has adjusted to 14.6 mpg instreets now at 15k mileage, but i suspect it is just due to my getting familiar with the way it drives
17.5 - 22 mpg highway but i tend to drive at 70-75mph.
I would give it a few thousand miles for you to adjust to the truck. i do commute on very swervy and hilly instreets so i have been avoiding premee wear of the brakes and the tickets....and i do fill up with 87 exclusively. i chuck in a fuel cleaner every now and then and have a catchcan. doubt these improve fuel econ