Poor Idle Quality

FAULT INDICATIONS
Idle speed uneven, too high, or too low.

FAULT TRACING CONDITIONS
Before fault tracing, ensure that:
^ No diagnostic trouble codes are present,
^ The engine is at operating temperature, and
^ All fuses are clean and intact.

UNEVEN IDLE SPEED
^ Faulty spark plugs
^ Blocked injectors
^ Poor/uneven compression
^ Faulty secondary ignition components
^ Faulty EGR valve
^ Faulty sensor signals

IDLE SPEED TOO HIGH
^ Throttle cable sticking
^ Throttle body incorrectly adjusted
^ Intake air leakage
^ Faulty idle air control valve

IDLE SPEED TOO LOW
^ Throttle body incorrectly adjusted
^ Faulty idle air control valve