High HC & CO - at High RPM

This condition, abnormally high Carbon Monoxide and Hydrocarbons during cruise (2500 rpm), may indicate a problem in one or more of the areas listed below.

POSSIBLE CAUSE ACTION


Electrical misfires Check ignition system. Refer to IGNITION SYSTEM



Vacuum leak Check intake manifold and vacuum components.



Faulty canister purge system Check Evaporative System.



PCV malfunction Check PCV system.



EGR malfunction Check EGR system.



Restricted exhaust Check exhaust system for a restriction.



Incorrect spark timing Check Spark Controls (EST, ESC etc..). Refer to COMPUTERS AND CONTROL SYSTEMS, &/or see IGNITION SYSTEM.



Fuel metering malfunction