GMC 2003 Envoy - Manual (Page 276)

Sdcw can trap ekhau^t gases under your
vehicle. This can cause deadly CO (carbon
monoxide) gas to get insfde. CO could
Overcome you and kill you. You can't see it or
smell it, so you might not know it Is In your
vehicle. Clear away snow from around the
base of your vehicle, espeoialty any that is
blocking your exhaust pipe. And check around
again From time to time to be sure snow
doesn't collect there.
Open a window Jusi a little on the side of the
vehicle that's away from the wind. This will
help keep CO out-
Run your engine only as long as you must. Tfiis saves
fuel. When you run the engine, make it go a little
faster than just Idle. That is, push the ancelsrator
slightly. This uses less fuel for Ihe heat lhal you get and
it keeps the battery charged. You
wi'in need a
well-charged battery lo restart the vehicle, and possibly
for signaling later on with your headlamps. Let the
heater run for
a whits.
Then, shul the engine off and ctose ihe window almost
all the way lo preserve the heal. Elart The engine
again and repeat this only when you feel really
urreomfortable from the cold But do it as liltle as
possible. Presarva jhe fuel long
as you can. Tq help
keep warm, you can get out of the vehicle and do
some fairly vigofous exercises every half hour or so until
help comes.
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