High HC and CO - at High RPM

Condition: Abnormally high carbon monoxide AND hydrocarbon emissions during cruise (2500 rpm).

POSSIBLE CAUSE ACTION


Electrical misfires Check ignition system



Vacuum leak Check intake manifold
and vacuum components.
Check vacuum hose routing.
See SCHEMATIC DIAGRAMS.



Faulty canister purge system Check evaporative emission system.



PCV malfunction Check PCV system.



Restricted exhaust Check catalytic converter.


Initial timing incorrect Check Ignition Timing.
See ADJUSTMENT PROCEDURES.



Incorrect Spark Advance Refer to
COMPUTERIZED ENGINE CONTROLS.



Verify vehicle remains in Refer to
Closed Loop at steady throttle COMPUTERIZED ENGINE
(2500 rpm), oxygen sensor operation CONTROLS
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 clean)