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 See Evaporative Emissions System


PCV malfunction See Positive Crankcase Ventilation



Restricted exhaust See Catalytic Converter



Incorrect Spark Advance See Ignition System.



Verify vehicle remains in Closed
Loop at steady throttle (2500 rpm)
and oxygen sensor is working.



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