Ford Mustang Owner's Manual page 173

Maintenance and Specifications
battery is disconnected or a new battery is installed,
the engine must relearn its idle and fuel trim
strategy for optimum driveability and performance.
To begin this process:
1. With the vehicle at a complete stop, set the
parking brake.
2. Put the gearshift in P (Park) (automatic
transmission) or the neutral position (manual
transmission), turn off all accessories and start the
engine.
3. Run the engine until it reaches normal operating
temperature.
4. Allow the engine to idle for at least one minute.
5. Turn the A/C on and allow the engine to idle for
at least one minute.
6. Drive the vehicle to complete the relearning
process.
• The vehicle may need to be driven 16 km
(10 miles) or more to relearn the idle and fuel
trim strategy.
• If you do not allow the engine to relearn its
idle trim, the idle quality of your vehicle may
be adversely affected until the idle trim is
eventually relearned.
When the battery is disconnected or a new battery
installed, the transmission must relearn its adaptive
strategy. As a result of this, the transmission may
shift firmly. This operation is considered normal and
will not affect function or durability of the
transmission. Over time the adaptive learning
process will fully update transmission operation to
its optimum shift feel.
If the battery has been disconnected or a new
battery has been installed, the clock and the preset
radio stations must be reset once the battery is
reconnected.
2004 Mustang (mus)
Owners Guide (post-2002-fmt)
USA English (fus)
173