2008 GMC Envoy Owner's Manual - Page 112

Running the Vehicle While Parked It is better not to park with the engine running. But if you ever have to, here are some things to know. {CAUTION: It can be dangerous to get out of your vehicle if the shift lever is not fully in PARK (P) with the parking brake firmly set. Your vehicle can roll. Do not leave your vehicle when the engine is running unless you have to. If you have left the engine running, the vehicle can move suddenly. You or others could be injured. To be sure your vehicle will not move, even when you are on fairly level ground, always set the parking brake and move the shift lever to PARK (P). {CAUTION: Idling the engine with the climate control system off could allow dangerous exhaust into your vehicle. See the earlier caution under Engine Exhaust on page 2-37. Also, idling in a closed-in place can let deadly carbon monoxide (CO) into your vehicle even if the climate control fan is at the highest setting. One place this can happen is a garage. Exhaust - with CO - can come in easily. NEVER park in a garage with the engine running. Another closed-in place can be a blizzard. See Winter Driving on page 4-30. 2-38