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


Rich operating condition ^ Check oxygen sensor and feedback system. Refer to COMPUTERS AND CONTROL SYSTEMS
Excessive fuel pressure ^ Check fuel pressure regulator and return line.
Leaking fuel injector(s) ^ Refer to FUEL SUPPLY AND AIR INDUCTION/DIAGNOSIS, TESTING AND INSPECTION PROCEDURES/TESTING PROCEDURES/FUEL INJECTOR BALANCE TEST.



Dirty air filters ^ Clean or replace.



Saturated fuel evaporative canister
or malfunctioning vapor purge system ^



Stuck or restricted [1][2]PCV ^ Check PCV system
valve and/or hose Testing and Inspection