High CO and HC - at Idle

This condition, at idle, is indicated by abnormally high carbon monoxide AND hydrocarbon emissions.

POSSIBLE CAUSE ACTION

VERY RICH Air-Fuel mixture Check Air/Fuel ratio,
perform injector balance test,
inspect regulator operation
(check vacuum line and return hose),
check fuel pressure



Malfunctioning AIR system Check Air Injection system



Faulty Fuel Evaporative system, Check Evaporative Control system
vapor lines, purge solenoid
and/or valves



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



Engine misfire with Closed Loop Refer to rich exhaust trouble
fuel metering system, causing system code, check oxygen
to go full rich sensor