High CO and HC - at High RPM

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

POSSIBLE CAUSE ACTION



ECCS system malfunction. Refer to On Board Diagnostics.



Electrical misfires. Check ignition system.



Vacuum leak. Check vacuum lines and routing in
"Vacuum and Vapor Hose Routing"
in Emissions also check intake manifold
and vacuum components.



Faulty canister purge system. Check evaporative emissions system.



PCV malfunction. Check PCV system.



EGR malfunction. Check EGR system.



Restricted exhaust. Check catalytic converter.



Initial timing incorrect. Check ignition timing.



Verify vehicle remains in
closed loop at steady throttle
(2000 rpm) and Heated Oxygen Sensors
are working. To test Heated Oxygen Sensors