Last year, Chevy's full-size Impala received a powertrain transplant. The new 3.6-liter V-6 brought with it 303 horsepower and competitive fuel economy numbers that aren't much better than prior versions of the big sedan, but remain the equal of vehicles like the Hyundai Azera and Toyota Avalon.
Those sedans earn EPA highway ratings of about 29 miles per gallon, and the Impala ranks slightly higher. The EPA puts the Chevy sedan at 18 miles per gallon on the city cycle, and 30 miles per gallon on the highway. That's down 1 mpg from the previous Impala, but 1 mpg higher on the highway cycle. We'd trade the current powertrain's smoothness and acceleration for the wider economy spread and two additional transmission gears any day.
The Impala remains E85 (85 percent ethanol) compatible, although running on the fuel it gets just 13/22 mpg.