High HC and CO at High RPM

This condition indicates abnormally high Carbon Monoxide and Hydrocarbons during cruise (2500 rpm).

POSSIBLE CAUSE ACTION


Electrical misfires Refer to IGNITION SYSTEM



Vacuum leak Check vacuum lines and routing. See Diagrams/Vacuum and Vapor Hose Diagrams.
Check intake manifold and vacuum components.



Faulty canister purge system Testing and Inspection



PCV malfunction Check PCV system. Testing and Inspection



Restricted exhaust Testing and Inspection



Incorrect Spark Advance Check Spark Controls (EST, ESC, etc...).



Fuel metering malfunction Check fuel pressure regulator and return line.
Perform injector balance test. Refer to FUEL SUPPLY AND AIR INDUCTION/DIAGNOSIS, TESTING AND INSPECTION PROCEDURES/TESTING PROCEDURES/FUEL INJECTOR BALANCE TEST.



EGR malfunction Check EGR system. Testing and Inspection