High CO and HC - At Idle

SYMPTOM:
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 test,
inspect regulator operation
(check vacuum line and return hose),
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 Positive Crankcase Ventilation Valve from crankcase
sucked through PCV valve and retest emissions


Engine misfire with Closed Loop Refer to "Computers and
fuel metering, causing system Control Systems"
to go full rich for rich trouble code,
check fuel feedback (Oxygen sensor)