1997 GMC Suburban Owner's Manual - Page 104

Running Your Engine While You're Parked It's better not to park with the engine running. But if arcthings to kn---'. It can be dangerous to get out your vehicle if of the shift leveris not fully in PARK (P) with the parking brake firmlyset. Your vehiclecan roll. Don't leave your vehicle when the engineis running unlessyou have to. If you've left the engine running, the vehicle can move suddenly. You or others could be injured. be sure your To vehicle won't move, even when you're on fairly level ground, always set your parking brake and move the shift lever to PARK (P). L A CAUl ION: Idling the enginewith the air system control off could allow dangerous exhaust into your vehicle (see the earlier Caution under "Engine Exhaust"). Also, idling in a closed-in place canlet deadly carbon monoxide (CO) into your vehicle even if the fan switch at the highest setting. One place is this can happen a garage. Exhaust with is CO can comein easily. NEVER park in a garage with the engine running. Another closed-in place can be a blizzard. (See "Blizzard" in theIndex.) -- 0- If you have four-wheel drive and your transfer case is in NEUTRAL (N), your vehicle will be free to roll, even if your shift lever is in PARK (P). So, be sure the transfer case is in a drive gear -- not in NEUTRAL (N). Always set your parking brake. Follow the proper steps to be sure your vehicle won't move. See "Shifting Into PARK (P)" in the Index. If you're pulling a trailer, see "Towing a Trailer" in the Index.