It is more that just mileage, includes pollution issues also.
"The company said Thursday that in September, a group of employees reported possible problems with a mathematical model used to calculate pollution and mileage, prompting the company to hire an outside firm to run tests. Testing will start with the 2019 Ford Ranger small truck, and if problems are found, the company will start looking at models dating to 2017."
2021 F150 2.7 Ecoboost - Summer Home 2017 Bighorn 3575el. Can Am Spyder RT-L Chrome, Kawasaki KRX1000. Retired and enjoying it! RIP DW 07-05-2021