Ford 2003 Mustang Workshop Manual page 72

described as
piston slap. Noise
is most
noticeable when
engine is cold
with light to
medium
acceleration.
Noise disappears
as engine warms
Knocking noise—
light double
knock or sharp
rap sound.
Occurs mostly
with warm engine
at idle or low
speeds in DRIVE.
Increases in
relation to engine
load. Associated
with poor
lubrication history
Knocking noise—
light knocking
noise is most
noticeable when
engine is warm.
Noise tends to
decrease when
vehicle is
coasting or in
neutral
Knocking—deep
knocking noise.
Noise is most
noticeable when
engine is warm,
at lower rpm and
under a light load
and then at float
Knocking noise—
occurs mostly
with warm engine
at light/medium
acceleration
Whine or
moaning noise
Excessive clearance
between the piston
and the piston pin.
Excessive clearance
between the
connecting rod
bearings and the
crankshaft.
Worn or damaged
crankshaft main
bearings.
Spark plugs.
Carbon accumulation
in combustion
chamber.
Air intake system.
injector connector until the
noise goes away. CARRY
OUT a cylinder bore
clearance to piston check.
INSTALL a new piston.
REFER to Section 303-01A
for 3.8L engines or Section
303-01B for 4.6L (2V)
engines.
INSTALL a new piston or
piston pin. REFER to
Section 303-01A for 3.8L
engines or Section 303-01B
for 4.6L (2V) engines.
Engine warm and at idle.
Using an EngineEAR,
PULL a spark plug or fuel
injector connector until the
noise goes away. INSTALL
new bearings. REFER to
Section 303-01A for 3.8L
engines or Section 303-01B
for 4.6L (2V) engines.
CARRY OUT DERU test.
CHECK for noise with
vehicle at operating
temperature, during
medium to heavy
acceleration. CHECK at
idle with injector
disconnected, noise does
not change. INSTALL new
main bearings. REFER to
Section 303-01A for 3.8L
engines or Section 303-01B
for 4.6L (2V) engines.
CHECK the spark plug for
damage or wear. INSTALL
new spark plugs as
necessary.
REMOVE carbon from
combustion chamber.
CHECK the air cleaner and
ducts for correct fit.
INSPECT the air intake
system for leaks or
damage. REPAIR as
necessary.