High HC - at High RPM

This condition indicates abnormally high Hydrocarbons with low or normal CO during cruise (2500 RPM).

POSSIBLE CAUSE ACTION


Electrical misfires ^ Check ignition system


Vacuum leak ^ Check vacuum lines and routing. SEE Diagrams/Vacuum and Vapor Hose

^ Check intake manifold and vacuum components


PCV malfunction ^ Check PCV system. Positive Crankcase Ventilation


Incorrect Spark Advance ^ Check Spark Controls.


EGR malfunction ^ Check EGR system. Exhaust Gas Recirculation