High CO & HC - at Idle

This condition, at idle, indicates abnormally high Carbon Monoxide and Hydrocarbons.

POSSIBLE CAUSE ACTION


Very rich Air-Fuel mixture ^ Check Air-Fuel ratio, O2 sensor, perform injector balance test, inspect regulator operation (check vacuum line and return hose), check fuel pressure.


Faulty Fuel Evaporative system, ^ Check Fuel
vapor lines, purge solenoid Evaporative system.
and valves Evaporative Emissions System


Fuel in crankcase being ^ Remove PCV Valve
sucked through PCV Valve from crankcase
and retest emissions


Dirty air filters ^ Clean or replace