High CO, Low or Normal HC -- at Idle

This condition, at idle, is indicated by abnormally high carbon monoxide emissions while the hydrocarbon emissions remain normal or low.

POSSIBLE CAUSE
Malfunctioning closed loop fuel metering system
Exhaust leak or other false indicators "Fooling" oxygen sensor to sense a lean condition

ACTION
Check exhaust system for leaks.
Check closed loop metering system.



POSSIBLE CAUSE CAUSE
Rich Air-Fuel mixture

ACTION
Check Air/Fuel ratio.
Perform injector balance test
Test regulator operation (check vacuum line and return hose)
Check fuel pressure.



POSSIBLE CAUSE
Dirty air filter(s)

ACTION
Clean or replace



POSSIBLE CAUSE
Saturated fuel evaporative canister or malfunctioning vapor purge system

ACTION
Check Evaporative system. Evaporative Emissions System



POSSIBLE CAUSE
Stuck or restricted PCV

ACTION
Check PCV system. Positive Crankcase Ventilation