High HC & CO - at High RPM

Symptom: High Carbon Monoxide and Hydrocarbons during cruise (2500 RPM).

POSSIBLE CAUSE ACTION


Electrical misfires ^ Check ignition system.
SEE Ignition System / testing and Inspection / Oscilloscope Patterns.


Initial timing incorrect ^ Check base timing.
SEE Ignition System / Adjustments.

^ Check Timing belt alignment.


Incorrect Spark Advance ^ Check Spark Controls.
SEE Ignition System / Specifications


Vacuum leak ^ Check vacuum lines and routing.
Refer to Vehicle Emission Control Information (VECI) label under hood.

^ Check intake manifold
and vacuum components


Faulty EVAP Canister purge system ^ Check Fuel Evaporative System.


Restricted exhaust ^ Check Catalytic Converter.


EGR malfunction ^ Check EGR system.


[1][2]PCV malfunction ^ Check PCV system.


Fuel Injection malfunction ^ Check fuel pressure.

^ Perform injector balance test.

^ Service Fuel Injectors (Pressure cleaner).