High CO - at High RPM

SYMPTOM:
This condition is indicated by abnormally high carbon monoxide with low or normal hydrocarbon emissions during cruise (2500 rpm).


POSSIBLE CAUSE ACTION



PCV malfunction Check Positive Crankcase Ventilation (PCV) system in "Testing
Procedures"

EGR malfunction Check Exhaust Gas Recirculation (EGR) system in "Testing
Procedures"

Restricted exhaust Check Three Way Catalytic Converter in
"Testing Procedures"


Verify vehicle remains in Refer to
Closed Loop at steady throttle "Computers And Control Systems" for
(2500 rpm) and oxygen sensor Self-Diagnostic procedures
is working


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