Rough, Unstable or Incorrect Idle; Stalling

Definition: The engine runs unevenly at idle. If bad enough, the vehicle may shake. Also, the idle may vary in rpm. Either condition may be severe enough to cause stalling. Engine idles at incorrect speed.

POSSIBLE CAUSE ACTION

Throttle linkage sticking/binding ^ Check and adjust, refer to ADJUSTMENT PROCEDURES

Fuel Metering ^ Check air/fuel ratio, (O2 Sensor Voltage)
^ Perform INJECTOR BALANCE TEST,
^ Check vacuum line and return hose,
^ Check fuel pressure

Incorrect idle speed ^ Check and adjust, refer to ADJUSTMENT PROCEDURES