Ford 2003 Mustang Workshop Manual page 75

Accelerator pedal
vibration—felt
through the pedal
as a buzz
Engine
vibration—mostly
at coast/neutral
coast. Condition
improves with
vehicle
accelerating
Engine vibration
or shudder—
occurs with light
to medium
acceleration
above 56 km/h
(35 mph)
Symptom Chart—Idle Noise/Vibration
Condition
Idle air control (IAC)
valve moan — occurs
on throttle tip-out
Accessory drive belt
chirp — occurs at idle
or high idle, cold or
hot. Most common
occurrence is during
humid weather
Accessory drive
bearing hoot —
occurs at idle or high
idle in cold
temperatures of
approximately +4°C
Throttle cable loose
or misrouted.
Combustion
instability.
Worn or damaged
spark plugs.
Plugged fuel injector.
Damaged spark plug
wire.
Contaminated fuel.
Worn or damaged
torque converter.
Possible Sources
IAC valve is
contaminated
with oil.
Accessory drive
belt worn, or
pulley is
misaligned or
loose.
Accessory drive
idler or
tensioner pulley
bearing is
experiencing
stick/slip
as necessary.
INSPECT the throttle cable.
REPAIR as necessary.
REFER to Section 310-02
CHECK the ignition system.
INSTALL new components
as necessary.
INSPECT the spark plugs
for cracks, high resistance
or broken insulator.
INSTALL a new spark plug
(s) as necessary.
REPAIR or INSTALL a new
injector as necessary.
REFER to Section 303-04A
for 3.8L engines or Section
303-04B for 4.6L (2V)
engines.
INSPECT the spark plug
wires for damage. INSTALL
a new spark plug wire(s) as
necessary.
INSPECT the fuel for
contamination. DRAIN the
fuel system and refill.
CHECK the torque
converter. INSTALL a new
torque converter as
necessary. REFER to
Section 307-01
.
Action
GO to Component Tests in
this section.
INSPECT for loose or
misaligned pulleys. CHECK
the drive belt for wear or
damage. INSTALL new
pulley(s)/drive belt, or
accessory drive components
as necessary. REFER to
Section 303-05 .
Go To Pinpoint Test C
.
.