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 Check evaporative emission system.



PCV malfunction Check PCV system.



Restricted exhaust Check catalytic converter.



Incorrect Spark Advance Refer to COMPUTERIZED ENGINE CONTROLS.



Verify vehicle remains in Refer to COMPUTERIZED
Closed Loop at steady throttle ENGINE CONTROLS
(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)
Refer to FUEL SYSTEMS