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 Check ignition system.
[1][2]C Charts



Vacuum leak Check vacuum lines and routing.See DIAGRAMS.
Check intake manifold and vacuum components.



[1][2]PCV malfunction Check PCV system.
Testing and Inspection


EGR malfunction Check EGR system.
Testing and Inspection



Restricted exhaust Check exhaust system for a restriction.
Testing and Inspection



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



Fuel metering malfunction Check fuel pressure.
Inspect pressure regulator operation
(check vacuum line and return hose).
[1][2]Chart A-7 Fuel System Diagnosis
Service Fuel Injector (Pressure clean).