FUEL EFFICIENT 22 MPG Hwy/17 MPG City! SLE trim. iPod/MP3 Input, Satellite Radio, Flex Fuel, 4x4, Aluminum Wheels, Back-Up Camera. KEY FEATURES INCLUDE4x4, Back-Up Camera, Flex Fuel, Satellite Radio, iPod/MP3 Input. EXPERTS RAVEAt highway speeds, we found the Sierras cabin remarkably quiet and comfortable, while the trucks suspension easily absorbed minor road distortions. -KBB.com. Fuel economy calculations based on original manufacturer data for trim engine configuration. Please confirm the accuracy of the included equipment by calling us prior to purchase.