High CO -- at High RPM

Condition: Abnormally high carbon monoxide with low or normal hydrocarbon emissions during cruise (2500 rpm).


POSSIBLE CAUSE ACTION


Faulty canister purge system See Evaporative Emission Control System



PCV malfunction See Positive Crankcase Ventilation System



EGR malfunction See Exhaust Gas Recirculation System



Restricted exhaust See Three-Way Catalytic Converter



Incorrect Spark Advance See Computers and Control Systems



Verify vehicle remains in See Computers and Control Systems
Closed Loop at steady throttle
(2500 rpm) and oxygen sensor
is working




Fuel metering malfunction Check fuel pressure
Perform injector balance test
Test pressure regulator operation
(check vacuum line and return hose),
Service Fuel Injectors (Pressure cleaner)
See Fuel Systems