1998 GMC Envoy Owner's Manual - Page 86

Running Your Engine While You're Parked It's better not to park with engine running. But the if ever you have to, here are some thingsto know. It can be dangerous to get out of your vehicle if the shiftlever is not fully in PARK (P) with the parking brake firmly set. Your vehicle can roll. Don't leave your vehicle when the engine is running unless you have to. If you've left the engine running, thevehicle can move suddenly. You or otherscould be injured. To be sure your vehicle won't move, even when you're fairly on level ground, always set your parkingbrake and move the shiftlever to PARK (P). Follow the proper steps to be sure your vehicle won't move. See "Shifting Into PARK (P)" in the Index. A CAUTION: Idling theengine with the airsystem control off could allowdangerous exhaust into your vehicle (seethe earlier Caution under "Engine Exhaust"). Also, idling in a closed-in place can letdeadly carbon monoxide (CO)into yourvehicle evenif the fanswitch is at the highest setting. One place this can happen a garage. Exhaust with is CO can come in easily. NEVER park ina garage with the engine running. Another closed-in place can be a blizzard. (See L6BlizzardSS inIndex.) the -- -- If you're pulling a trailer, see "Towing a Trailer" in the Index. 2-25