Rough, Unstable, or Incorrect Idle, Stalling

The engine runs unevenly. If bad enough, the car may shake. The engine idle may hunt or fluctuate in rpm and may be bad enough to stall.

POSSIBLE CAUSE ACTION


AT ALL TIMES
EGR malfunction, Check EGR system
Flange gasket leaking, Exhaust Gas Recirculation
Valve open (valve should
be closed at idle)



Air management valves Check Air Injection system
malfunctioning, no
air to ports while
in closed loop



PCV valve malfunction Check PCV system
Testing and Inspection



AT OPERATING TEMPERATURE
Faulty canister purge Check Evaporative system
and vent valve Evaporative Emissions System




Restricted exhaust system Check Catalytic Converter system
Testing and Inspection



Idle speed too low Check idle load compensator devices
Testing and Inspection