High CO and HC at Idle

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

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, Check fuel evaporative system
vapor lines, purge solenoid
and valves



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



Engine misfire with Closed Loop fuel Perform Self-diagnostic procedure
metering, causing system to go full rich