Sadly, the 300-plus-horsepower V-8 SS model is no longer included in the 2010 Chevrolet Impala lineup, but thankfully, the model has other positives. Two engine configurations can be chosen with the 2010 Chevrolet Impala: the standard 3.5-liter V-6 found in base models and another 3.9-liter V-6 that comes standard in the top-of-the-line LTZ version only. A four-speed automatic transmission is the only option, which is disappointing against newer six-speed autos in many rival models.
The 3.5-liter unit is rated at 211 horsepower and 216 pound-feet of torque, returning fuel economy figures of 18 mpg in the city, 29 mpg on the highway, and 22 mpg combined. The 3.9-liter mill produces 230 horsepower and 235 pound-feet of torque and returns fuel economy of 17 mpg in the city, 27 mpg on the highway, and 21 mpg combined.
Both engines in the Impala offer decent performance, with the only downside being a certain roughness while accelerating, though it must be noted that while cruising, the engines are rather smooth. The 3.9-liter offers noticeably more torque off the line, which may be more useful with a full load. Car and Driver claims "the idea of the base 211 horsepower, 3.5-liter V-6 would drop our eyelids, [but] the 3.9-liter V-6 is not a bad choice in this car ... it feels strong, even at higher rpm and speed, and never sounds labored," adding that its "233 horsepower is enough to giddyap to 60 mph in 7.4 seconds." Edmunds states that it’s “plenty powerful.” ConsumerGuide finds that the "3.5 and 3.9-liter V6s provide similar acceleration in around-town driving, but the 3.9 has better passing response in the 35-55-mph range." All Impala engines are capable of running on E85 ethanol fuel.
Car and Driver reports that "a four-speed automatic is standard on all Impalas," and Cars.com tells us it "works with all engines." Edmunds notes, “All models employ front-wheel drive and a responsive four-speed automatic transmission.” Many competitors offer six-speed automatics in the class, however.
ConsumerGuide tests find that "an LT 3.5 averaged 24.2 mpg on conventional gasoline in mostly highway driving," which drops significantly using E85. The 3.9-liter V-6 uses Active Fuel Management technology to shut down one bank of cylinders when coasting or cruising at freeway speeds, which "increases gas mileage by as much as eight percent," reports Cars.com.
ConsumerGuide finds the Impala "stable with good steering feel," adding "stopping control is good." Edmunds claims "cushy suspension hurts handling dynamics.” According to Car and Driver, "the Impala soaks up bumps well" when traveling in a straight line, but "once the road starts to wind, the Impala dips, leans, and squats as though the road were one big yoga mat."