I bought a new 2021 F-150 with the power boost (hybrid) setup. Currently, the truck has 2500 miles on it. I towed my camper this past weekend for the first time and got poor gas mileage. My previous truck was a 2017 F-150 with the 3.5 eco-boost engine. When I towed my camper, I set the cruise control for 67 MPH and I got 9 to 10 MPG. This time I set the cruise control for 67 MPH and I only got 6.5 MPG. On the return trip I slowed down to 60 MPH and I got 10.2 MPG. It's the same engine except I have the extra electric motor, why the poor gas mileage? Any suggestions out there?

 

What's the final rear end ratio? I would give your truck a little more time. The engine isn't really fully broken in and you gave it a tough task to do. I would expect your mileage to improve as the engine gets fully broken in.

 

this truck and the previous truck both have the 3.55 rear differential, so thats the same. when i was driving at 67 MPH the tach had 2200 RPM. when i slowed down to 60 MPH, the tach read 1900 RPM

 

I would wait, allow the engine proper break in and then see what kind of mileage you get. Your engine seems to be loafing along at 1900-2200 RPM at freeway speeds. I don't know where you are located but the engine will take much longer to warm up and run efficiently in cold temperatures. I trust that you ruled out jack rabbit starts and warming up the truck in the driveway for 20 minutes before hitting the road which seems to be a habit of many drivers today.