1994 GMC Sonoma Owner's Manual - Page 62

How long should you keep the coolant heater plugged in? The answer depends on the weather, the kind of oil you have, and some other things. Instead of trying to list everything here, we ask that you contact a GM dealer in the area where you'll be parking your vehicle. The dealercan give you the best advice for that particular area. Automatic Transmission There are several different positions for your shift lever. P (Park) This locks your rear wheels. It's the best position to use when you start your engine because your vehicle can't move easily.