2008 Chevrolet Impala Owner's Manual - Page 100

Active Fuel Management™ (3.9L V6 and 5.3L V8 Engines) Your vehicle's engine may be equipped with Active Fuel Management™. This system allows the engine to operate on either all or half of its cylinders, depending on your driving conditions. When less power is required, such as cruising at a constant vehicle speed, the system will operate in the half cylinder mode, allowing your vehicle to achieve better fuel economy. When greater power demands are required, such as accelerating from a stop, passing, or merging onto a freeway, the system will maintain full-cylinder operation. Automatic Transmission Operation Your automatic transmission has a shift lever on the steering column or on the console between the seats. There is a display, located on the instrument panel cluster that will indicate the gear the vehicle is in. Maximum engine speed is limited on automatic transmission vehicles while you are in PARK (P) or NEUTRAL (N) to protect driveline components from improper operation. There are several different positions for the shift lever. 2-26