High HC & CO - at High RPM

This condition is indicated by abnormally high carbon monoxide AND hydrocarbon emissions during cruise (2500 rpm).

POSSIBLE CAUSE ACTION


Electrical misfires Check ignition system



Vacuum leak Check vacuum lines and routing in
"Vacuum and Vapor Hose Routing"
Check intake manifold
and vacuum components





PCV malfunction Check PCV system in "Testing
Procedures"





Restricted exhaust Check Catalytic Converter in
"Testing Procedures"



Initial timing incorrect Check Ignition Timing in "Adjustment
Procedures"




Incorrect Spark Advance Check Ignition Timing in "Adjustment
Procedures"




Verify vehicle remains in Test Fuel Injection for rich trouble code
Closed Loop at steady throttle Self-Diagnostic procedures
(2500 rpm), oxygen sensor operation
is working






Fuel metering malfunction Check fuel pressure
Fuel Injected Perform injector balance test
Service Fuel Injectors (pressure clean)