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

Fuel Injected Check air/fuel ratio,
Refer to Computers and Control Systems
Check fuel pressure,
(check vacuum line and return hose)

Incorrect idle speed Check and adjust