High CO and HC - at Idle

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



Faulty Fuel Evaporative system,
vapor lines, purge solenoid
and/or valves See Evaporative Emissions System



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



Engine misfire with Closed Loop
fuel metering, causing system
to go full rich
See Computers and Control Systems