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, perform injector balance test, inspect regulator operation (check vacuum line and return hose), check fuel pressure.

Refer to Fuel Delivery and Air Induction, Testing and Inspection


Dirty air filter Clean or replace



Saturated fuel evaporative
canister or malfunctioning
vapor purge system Evaporative Emission Control Canister
Canister Purge Control Valve