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



PCV valve malfunction Check PCV system in "Testing
Procedures"



Faulty canister purge Check Evaporative system in
valve (at operating temperature) "Testing Procedures"



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



Idle speed too low Check idle speed in "Testing Procedures" and
in "Adjustment Procedure"