High CO - at High RPM

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

POSSIBLE CAUSE ACTION

Faulty bowl vent/canister Check Evaporative System in
purge system "Testing Procedures" in Emissions




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



Incorrect Spark Advance Check Spark Controls in
"Fuel Injection and Computers
and Control Systems"



Verify vehicle remains in Refer to "Fuel Injection and
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)