CONTENTS
SOUNDS
UNDERHOOD
RHYTHMIC

ROUGH IDLE

CONDITION(S)

• ENGINE HAS ROUGH IDLE
• ROUGHNESS SMOOTHES OUT WHEN ENGINE SPEED IS INCREASED

POTENTIAL CAUSE(S)

CHECK THESE FIRST:

1. DIRTY OR IMPROPERLY GAPPED SPARK PLUGS
Clean or replace spark plugs.

2. CLOGGED OR LEAKING FUEL INJECTORS
Have fuel injectors professionally replaced.

3. SHORTED OR DISCONNECTED FUEL INJECTOR COILS
Have fuel injector coils professionally serviced.

4. CLOGGED AIR CLEANER FILTER
Replace air cleaner filter.

5. BROKEN OR DISCONNECTED SPARK PLUG WIRE
Connect spark plug wire or replace if necessary.

6. EXHAUST GAS RECIRCULATION (EGR) VALVE STUCK OPEN
Have EGR valve professionally serviced.

7. CLOGGED IDLE CIRCUIT IN CARBURETOR; CONFIRMED IF CAR ALSO STALLS AT LOW SPEEDS
Clean carburetor with solvent.
Have carburetor professionally repaired.

8. FAULTY POSITIVE CRANKCASE VENTILATION (PCV) VALVE
Replace PCV valve.

CHECK THESE NEXT:

CHECK THESE LAST:

CONTENTS
HALLOW, RAPPING SOUND
LIGHT, DOUBLE-CLICKING SOUND