High CO and HC - at Idle

This condition, at idle, indicates abnormally high Carbon Monoxide (CO) and Hydrocarbons (HC).

POSSIBLE CAUSE ACTION

Fuel Metering 1. Check Air/Fuel ratio, fuel pressure, and check regulator pressure.
2. Perform Injector Balance Test.
3. Service Fuel Injectors (Pressure Cleaner).



Faulty Fuel Evaporative system,
vapor lines, purge solenoid
and valves 1. Check Fuel Evaporative system. See Evaporative Emissions System.
If OK, go to step 2.
2. Check Evaporative System electronic controls.


Fuel in crankcase being
sucked through PCV valve Remove PCV from crankcase and retest emissions.



Engine misfire with Closed Loop
fuel metering, causing system
to go full rich Check fuel feedback (oxygen sensor).