Ford 2003 Mustang Owner's Manual page 113

To put your vehicle in gear, start the engine, depress
the brake pedal, then move gearshift out of P
(Park).
Hold the brake pedal down while you move
the gearshift lever from P (Park) to another
position. If you do not hold the brake pedal down,
your vehicle may move unexpectedly and injure
someone.
Understanding gearshift positions
P (Park)
Always come to a
complete stop before
shifting into P (Park).
Make sure the gearshift
is securely latched in P
(Park). This locks the
transaxle and prevent
the front wheels from
rotating.
Always set the
parking brake
fully and make sure
the gearshift is
latched in P (Park).
Turn off the ignition
whenever you leave
your vehicle.
Driving
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