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 Air-Fuel mixture Check Air/Fuel ratio
inspect pressure regulator operation,
(check vacuum line and return hose),
check fuel pressure.
[1][2]Chart A-7 Fuel System Diagnosis



Dirty air filters Clean or replace.



Saturated fuel evaporative canister Check evaporative system.
Testing and Inspection




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