High HC and CO at High RPM

DEFINITION: Abnormally high Carbon Monoxide and Hydrocarbons during cruise (2500 rpm).

POSSIBLE CAUSE ACTION


Electrical misfires Check ignition system.



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



Canister purge system See Evaporative Emissions System Evaporative Emissions System


PCV malfunction See Positive Crankcase Ventilation Positive Crankcase Ventilation



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.
Perform injector balance test.
Inspect regulator operation
(check vacuum line and return hose).
Service Fuel Injectors (Pressure clean).