High CO at High RPM

This condition indicates abnormally high Carbon Monoxide with low or normal Hydrocarbons during cruise (2500 rpm).

POSSIBLE CAUSE ACTION

[1][2]PCV malfunction Check PCV system



EGR malfunction Check EGR system



Restricted exhaust Check catalytic converter



Incorrect Spark Advance Check spark controls (EST ESC)



Verify vehicle remains in Closed Loop Perform Self-Diagnostic procedures
at steady throttle (2500 rpm) and
oxygen sensor is working



Fuel metering malfunction Check fuel pressure
Perform injector balance test
Inspect regulator operation
(check vacuum line and return hose),
Service Fuel Injectors (Pressure cleaner)