High CO and HC at Idle

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

POSSIBLE CAUSE ACTION

VERY RICH Air-Fuel mixture



Fuel Injected Check Air/Fuel ratio.
Inspect regulator operation. Check vacuum line and return hose.
Check fuel pressure.



Faulty Fuel Evaporative system, Check the Fuel Evaporative system
vapor lines, purge solenoid under TESTING PROCEDURES.
or valves.



Fuel in crankcase being Remove [1][2]PCV from crankcase
sucked through PCV valve and retest emissions.



Engine misfire with Closed Loop Refer to
fuel metering, causing system COMPUTERIZED ENGINE CONTROLS
to go full rich for rich trouble code.
Check fuel feedback (Oxygen sensor).