High CO, Low or Normal HC - at Idle

This condition, at idle, indicates abnormally high Carbon Monoxide while the Hydrocarbons remain normal or low.

POSSIBLE CAUSE ACTION


Fuel Metering Check Air/Fuel ratio,
verify fuel pressure,
inspect regulator operation
(check vacuum line and return hose),
Perform injector balance test
Service Fuel Injectors (Pressure cleaner)



Dirty air filters Clean or replace





Saturated fuel evaporative canister 1. Check Evaporative system
or malfunctioning vapor purge system under TESTING PROCEDURES. If OK, step 2
2. Check Evaporative System electronic controls.
Refer to COMPUTERIZED ENGINE CONTROLS.




Malfunctioning Closed Loop fuel metering Refer to COMPUTERIZED
system - Exhaust leak or other false ENGINE CONTROLS
indicators "Fooling" oxygen sensor to for testing of the computer
sense a lean condition feedback system.





Stuck or restricted PCV Check PCV system under TESTING
valve and/or hose PROCEDURES.