Ford 2003 Mustang Workshop Manual page 54

Neutral Coast Down Speed Test
To carry out this test, proceed as follows:
Drive at a higher rate of speed than where the concern occurred when carrying out the Slow
Acceleration Test.
Place the transmission in NEUTRAL and coast down past the speed where the concern occurs.
The concern is vehicle speed-related if duplicated while carrying out this test. This eliminates
the engine and the torque converter as sources.
If the concern was not duplicated while carrying out this test, carry out the Downshift Speed
Test to verify if the concern is engine speed related.
Proceed as necessary.
Downshift Speed Test
To carry out this test, proceed as follows:
Shift into a lower gear than the gear used when carrying out the Slow Acceleration Test.
Drive at the engine rpm where the concern occurs.
The concern is engine speed related if duplicated while carrying out this test. This eliminates the
tires, wheels, brakes and the suspension components as sources.
If necessary, repeat this test using other gears and NEUTRAL to verify the results.
Proceed as necessary.
Steering Input Test
To carry out this test, proceed as follows:
Drive at the speed where the concern occurs, while making sweeping turns in both directions.
If the concern goes away or gets worse, the wheel bearings, hubs, U-joints (contained in the
axles of 4WD applications), and tire tread wear are all possible sources.
Proceed as necessary.
Brake Test
To carry out this test, proceed as follows:
Warm the brakes by slowing the vehicle a few times from 80–32 km/h (50–20 mph) using light
braking applications. At highway speeds of 89–97 km/h (50–60 mph), apply the brake using a
light pedal force.
Accelerate to 89–97 km/h (55–60 mph).
Lightly apply the brakes and slow the vehicle to 30 km/h (20 mph).
A brake vibration noise can be felt in the steering wheel, seat or brake pedal. A brake noise can
be heard upon brake application and diminish when the brake is released.
Road Test Over Bumps
To carry out this test, proceed as follows: