Rough/Unstable Idle or 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 throttle linkage and cable

Fuel metering Check air/fuel ratio, by measuring 02 sensor voltage.
Perform injector service, (cleaning).
Check fuel pressure.

Incorrect idle speed Check minimum throttle body air flow.