Photo courtesy Ford Motor Co.
Ford's 2015 F-150, now in production, is class-leading among gasoline full-size pickups.

The top-selling vehicle in the U.S. now is also the most efficient gasoline pickup in the full-size category.

Equipped with an optional 2.7-liter V6 EcoBoost engine and two-wheel drive, it achieves 26 miles per gallon on the highway; equipped with a standard 3.5-liter V6, it gets up to 25 mpg, according to new ratings for the 2015 Ford F-150.

Switching to a lighter steel frame and aluminum body helped Ford improve the F-150's fuel burn and up max towing to a class-leading 12,200 lb.

Truck and auto makers are working under tightening federal regulations to double their corporate average fuel economy to 54.5 mpg by 2025. Chevrolet's new midsize truck, the 2015 Colorado, and its upscale twin, the 2015 GMC Canyon, get up to 27 mpg on highway with a 2.5-liter four-cylinder engine.

Chrysler's diesel Ram 1500 remains the most fuel-efficient pickup overall, hitting 28 mpg on highway, but "at today's fuel prices, Ram EcoDiesel owners are not able to offset the additional cost of their EcoDiesel engines with fuel savings," Ford insists.