1997 GMC Sonoma Owner's Manual - Page 82

Running Your Engine While You're Parked (Automatic Transmission) It's better not to park with the engine running. But if ever have to, here are somethings to know. Idling the engine withthe air system control off could allowdangerous exhaust into your vehicle (seethe earlierCaution under "Engine Exhaust"). Also, idling ina closed-in place can let deadly carbon monoxide (CO)into your vehicle even if the fan switch is at the highest setting. One place a this can happen.is garage. Exhaust with CO can come in easily. NEVER park in a garage with the engine running. Another closed-in placecan be a blizzard. (See "Blizzard" in the Index.) It can bedangerous to get out of your vehicle if the shift lever is not fullyin PARK (P) with the parking brake firmly set.Your vehiclecan roll. Don't leave your vehicle when engine is the running unless you have to. you've left the I f engine running, the vehicle can move suddenly. You or others could be injured. To be sure your vehicle won't move, even when you're fairly on level ground, always setyour parking brake and P. move the shift leverto PARK ( ) J -- -- If you have four-wheel drive with a manual transfer case shift lever and your transfer case is in NEUTRAL (N), your vehicle will be free to roll, even if your shift lever a is inPARK (P). So, be surethe transfer case is in 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.