Ford is facing a class-action lawsuit accusing the company of falsifying fuel economy tests on its popular F-150 pickup trucks, costing truck owners an extra $2,000 in fuel.

Why it matters: Ford, which declined comment, is already facing a federal criminal investigation over emissions testing procedures for its 2019 Ford Ranger after employees raised concerns. The new lawsuit alleges Ford inflated mpg ratings by as much as 15% on the Ford F-150, which is the best-selling vehicle in America.

The bottom line: Aside from the lawsuit, Ford could be facing a heavy fine if the U.S. Justice Department finds wrongdoing. Volkswagen and Fiat Chrysler Automobiles have already paid huge fines for falsifying emissions tests, and Daimler, the parent of Mercedes-Benz, faces similar scrutiny.