1998 GMC Jimmy Owner's Manual - Page 220

A CAUTION: Snow can trap exnaust gases under yourvehicle. This cancause deadly CO (carbon monoxide) gas and kill to get inside. CO could overcome you you. You can't see it or smell it, so you might not know it is in yourvehicle. Clear away snowfrom around the base of your vehicle, especiallyany that is blockingyour exhaust pipe. And check around again from time to time to be sure snow doesn't collectthere. Open a window just a little on the side of the vehicle that's away from thewind. This will help keep CO out. Run your engine only as long as you must. This saves fuel. When you run the engine, make it go a little faster than just idle. Thatis, push the accelerator slightly. This uses less fuel for the heat that you get and it keeps the battery charged. You will need a well-charged battery to restart the vehicle, and possibly for signaling later on with your headlamps. Let the heater run for a while. Then, shut the engine off and close the window almost all the way to preserve the heat. Start the engine again and repeat this only when you feel really uncomfortable from the cold. But do it as little as possible. Preserve the fuel as long as you can. To help keep warm, you can get out of the vehicle and do some fairly vigorous exercises every half hour or so until help comes. Recreatiorwl Vehicle Towing Vehicles with two-wheel drive or the electronic shift transfer case require special modifications before they can be towed in this manner. Please contact your dealer for the towing information that is appropriate foryour particular vehicle. 4-39