General Motors is firing the latest salvo in the new fuel economy war by upping the EPA numbers on the XFE Silverado and Sierra to 22 mpg in highway driving. The move also improves the combined fuel economy of the GMT900 trucks from 17 to 18 mpg. That number now matches the highway fuel economy of the Silverado hybrid, but without the really expensive battery pack.
Chevrolet spokesperson Brian Goebel told Pickuptrucks that the increased fuel economy is due several engineering improvements. The XFE's 5.3L V8 now has variable valve timing, optimized shift pattens in its 6-speed transmission, and Active Fuel Management, which enables the truck to run on four cylinders at cruising speeds.