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 canister purge system Check Evaporative System in
"Testing Procedures" in Emissions
PCV malfunction Check PCV 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
Test regulator operation
(check vacuum line and return hose),
Service Fuel Injectors (Pressure cleaner)