The 2015 Chevrolet Tahoe and GMC Yukon, along with the 2015 Suburban and Cadillac Escalade have received official fuel economy ratings from the EPA. According to General Motors, models equipped with the new all-aluminum 5.3-liter V-8 and two-wheel drive achieve 10 percent greater highway fuel economy, and 7 percent better mileage in the city compared to the previous base 5.3-liter engine.
That number for rear-drive Tahoe, Suburban, Yukon, and Yukon XL models with the 5.3-liter V-8 stands at 16/23 mpg city/highway. Add four-wheel drive, and that rating moves to 16/22 mpg for standard-wheelbase Tahoe and Yukon models, and 15/22 mpg for the lengthened Suburban and Yukon XL. The 5.3-liter V-8 also has a flex fuel option, which allows the engine to run on E85. When running that fuel, two-wheel-drive models achieve 12/17 mpg, while four-wheel-drive Tahoes and Yukons are rated at 11/16 mpg, and long-wheelbase Suburban and Yukon XL SUVs are rated at 11/15 mpg.
Available on the Denali trim for the Yukon and Yukon XL and standard on the 2015 Cadillac Escalade is an all-aluminum 6.2-liter V-8 producing 420 hp and 450 lb-ft of torque. That engine coupled with two-wheel drive is rated at 15/21 mpg. With four-wheel drive, the SUVs are rated at 14/21 mpg in standard-wheelbase form, and 14/20 mpg in Denali Yukon XL and Escalade ESV trims.
Source: GM, EPA