Active Fuel Management; Automatic Transmission Operation - GMC 2009 Envoy Denali Owner's Manual

Active Fuel Management™

The vehicle's V8 engine may have Active Fuel
Management™. This system allows the engine to
operate on either all or half of its cylinders, depending
on 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 the vehicle to achieve better
fuel economy. When greater power is required, such
as accelerating from a stop, passing, or merging onto a
freeway, the system will maintain full-cylinder operation.

Automatic Transmission Operation

There are several different
positions for the gear shift
lever.
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