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,
Fuel Injected check fuel pressure





Faulty Fuel Evaporative system, Check Fuel Evaporative system
vapor lines, purge solenoid in "Testing Procedures"
and valves



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



Engine misfire with Closed Loop Test the Fuel Injection and
fuel metering, causing system Ignition Systems
to go full rich for rich trouble code,
check fuel feedback (Oxygen sensor)