2003 GMC Sonoma Owner's Manual - Page 111

Running Your Engine While You Are Parked It's better not to park with the engine running. But if you here are some things to know. ever hav '0, It can be dangerous to get out your vehicle of if the shift leveris not fully in PARK (P) with the parking brake firmlyset. Your vehicle can roll. Don't leave your vehicle when the engine is running unless you haveto. If you've left the 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 on fairly level ground, always set your parking brake and move the shift lever to PARK (P). Idling the engine with the climate control system off could allow dangerous exhaust into your vehicle. See the earlier Caution under "Engine Exhaust.'' Also, idling in a closed-in place can let deadly carbon monoxide (CO) into your vehicle even if the fan is at the highest setting. One place this can happen i a garage. Exhaust - with s 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'' in the Index. Follow the proper steps to be sure your vehicle won't move. See Shifting Into Park (P) on page 2-32. If you're pulling a trailer, see Towing a Trailer on page 4-54. 2-36