http://www.preferredbuickgmc.com/ (616) 604-4260 Four trim levels exist, and all are powered by a 3.6-liter V6 with Variable Valve Timing (VVT) turning either the front wheels only, or all four when the conditions call for it, exclusively through a six-speed automatic transmission. With the former, the EPA estimates the Acadia will return 17 miles to the gallon in the city, while 24 miles will be covered for every gallon of gasoline burned on the highway. The all-wheel-drive models return 16 / 22 mpg respective numbers. That engine is good for a recently improved 288 horsepower at 6,600 rpm and 270 lb-ft at 3,200 rpm.