Ford 1996 Crown Victoria Manual page 251

Never get under a vehicle while it is
supported by a jack only. If you must work
under a vehicle, use safety stands.
Keep all lit cigarettes and other smoking
materials away from the battery and all
fuel-related parts.
Working with the engine off:
1. Set the parking brake fully and make sure
that the gearshift is securely latched in
P (Park).
2. Remove the key from the ignition after you
turn the engine off.
3. Block the wheels. This will prevent your
vehicle from moving unexpectedly.
Working with the engine on:
1. Set the parking brake fully and make sure
that the gearshift is securely latched in
P (Park).
2. Block the wheels. This will prevent your
vehicle from moving unexpectedly.
Do not start your engine with the air
cleaner removed and do not remove it
while the engine is running.
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