High CO - At High RPM

This condition indicates abnormally high Carbon Monoxide with low or normal Hydrocarbons during cruise (2500 rpm).

POSSIBLE CAUSE ACTION

Faulty canister purge system Check Evaporative System


PCV malfunction Check PCV system



EGR malfunction 1. Check EGR system
2. Check EGR electronic controls.



Restricted exhaust Check Catalytic Converter



Incorrect Spark Advance Check Spark Controls (SC).



Verify vehicle remains in Closed
Loop at steady throttle (2500 rpm)
and oxygen sensor is working See Computerized Engine Controls, Diagnosis and Testing.



Fuel Metering 1. Check Air/Fuel ratio, fuel pressure, and regulator operation.
2. Perform injector balance test.
3. Service fuel injectors (pressure cleaner).