Ford Grand Marquis Owner's Manual page 156

Have the exhaust and body ventilation systems
checked whenever:
your vehicle is raised for service
the sound of the exhaust system changes
your vehicle has been damaged in a collision
Improve your ventilation by keeping all air inlet
vents clear of snow, leaves, and other debris.
If the engine is idling while you are stopped in
an open area for long periods of time, open the
windows at least one inch (2.5 cm). Also, the
heating or air conditioning system should be set
to any function except MAX A/C or AUTO.
If you use the heater, set the fan speed on
MEDIUM or HIGH with the function control
on any position except OFF and the
temperature control at any desired position.
If you use the air conditioner, set the fan
speed on MEDIUM or HIGH with the
function control on any position except OFF
or MAX and the temperature control at any
desired position.
Pushing
Vehicles with automatic transmissions cannot be
started by pushing. Follow the directions under
If Your Vehicle Needs a Jump-Start.
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