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,
check intake manifold gasket,
carburetor base, and vacuum components



Faulty bowl vent/canister purge system Check Evaporative System


PCV malfunction Check PCV system



EGR malfunction Check EGR system


Restricted exhaust Check Catalytic Converter


Initial timing incorrect Check ignition timing
see Ignition Timing under
"ADJUSTMENT PROCEDURES"



Incorrect Spark Advance Check distributor advance mechanism,
vacuum hose, and routing



Verify vehicle is operating in Refer to "COMPUTERIZED ENGINE CONTROLS"
Closed Loop at steady throttle for Self-Diagnostic procedures
(2500 rpm) and oxygen sensor
is working




Fuel metering malfunction Check carburetor passages, bleeds
and restrictors, internal leaks,
float level, metering rods and gaskets
Replace or rebuild if faults are found