High CO - at High RPM

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


POSSIBLE CAUSE ACTION


PCV malfunction Check PCV system in "Testing
Procedures" in Emissions



EGR malfunction Check EGR system in "Testing
Procedures" in Emissions



Restricted exhaust Check Catalytic Converter in
"Testing Procedures" in Emissions




Fuel metering malfunction

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