Just returned from a 2100 mile trip to Florida. Using the cruise and Eco mode averaging 75-80mph truck computer said 19.4 average. Fuelly said 18.4 combined mileage for trip. Bed had our luggage, stroller, and cooler of beer. Very impressed with this truck and the ride was very comfortable.
5700 miles so far on my CCLB 350 with 3.55's and 295/65R20 on stock wheels. Everything else is stock for now. Just filled my DEF at 5600 miles for the first time, took 5 gallons. Honestly the truck is awesome, no complaints at all. Speedo isn't corrected but Fuelly says I'm averaging around 15...
Tried to buy my wife a 21 Expedition and they did the same thing. Same dealer where I bought my truck from! Told me sticker for Expedition and $10k less on trade. She has a 2019 Explorer Sport with 32k miles and it's spotless.