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 Diagrams"
- Check intake manifold
and vacuum components



Canister purge system Check Evaporative System in
"Testing Procedures"



PCV malfunction Check PCV system in "Testing
Procedures"



EGR malfunction Check EGR 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 Spark Controls in
"Computerized
Engine Controls"



Verify vehicle remains in Refer to
Closed Loop at steady throttle "Computerized Engine Controls" for
(2500 rpm), oxygen sensor operation Self-Diagnostic procedures
is working




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 clean)