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 ACTION


Rich Air-Fuel mixture


Carbureted Check Air/Fuel ratio, partially
closed choke high fuel level (float)
and dirty air bleeds




Dirty air filter(s) Clean or replace




Saturated fuel evaporative canister Check Evaporative system
or malfunctioning vapor purge system




Malfunctioning Closed Loop fuel Check computer feedback
metering system, exhaust leak or system
other false indicators causing
oxygen sensor to sense a lean
condition




Stuck or restricted PCV Check PCV system
valve and/or hose