Rough Unstable Idle

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

POSSIBLE CAUSE ACTION


AT ALL TIMES
PCV valve malfunction Check PCV system in "Testing
Procedures" in Emissions



AT OPERATING TEMPERATURE
Faulty canister purge Check Evaporative system in
and bowl vent valve "Testing Procedures" in Emissions



Restricted exhaust system Check Catalytic Converter system in
"Testing Procedure" in Emissions



Idle speed too low Check idle load compensator devices
in "Testing Procedures" and idle speed
in "Adjustment Procedure" in Emissions