Short answer- On the highway, I averaged about 22 MPG, not bad! The display mpg (lie-o-meter) averages an error of about +1 mpg.

I'm sharing my MPG data for each fill-up for anyone interested. (2018 2.7 L Ecoboost STX 4x4) I took a road trip from St. Louis MO to Austin TX and back. I logged my MPG data as seen below. I drove the speed limit pretty much the entire time, up to 75 mph. I had some headwinds and heavy rain from StL to Austin, and some tailwinds and no rain on the return trip from Austin to StL.



I'm pretty impressed! I had a 2001 F150 5.4L 4x4 that averaged about 16 mpg on the highway. Things have come a long way!

 

My last fill up I drove 363 miles all highway at 55mph put 12.408 gallons in the tank for an average of 29.25mpg '18 2.7L 3.55 rear

 

I'm RWD with the 3.73 e-locker. I get about 26+ highway at about 70mph. On my daily commute I get around 20-21.
Since my first fill up I have been using 89 octane. When gas prices spiked a few weeks ago I filled up with 87. The weather also spiked to 90+ and my mileage dropped to about 17 around town. Just refilled with 89 and my mileage is back up. The weather is sill in the 90s.

 

Been getting similar with my '18. These 2.7's really respond to the prudent driver.

The biggest smile for me came when pulling my 5K# tandem flatbed and got 18mpg! My buddy's Tundra doesn't even get that empty! I think he's about to make the jump...

 

Wow, you 2wd guys are getting REALLY good mileage! The best i can do is about 24 mpg, and that is driving hwy at <65 mph.

 

 

 

Any engine N/A or with a Power Adder will suck more gas going up hills that's just the way it is and always has been!!

 

And here I am happy with 14...

 

My best ever was 23.2 MPG. 600+ miles of interstate cruising between 70-75 MPH using 91 octane.