NCT fail, any guesses why?

Stallingrad

Brothers 2001 Punto failed its NCT with a CO reading of 13.31 on High Idle, off the scale (above .3% is a fail). Sensor was tested and is fine, any guesses as to what could be causing such a high reading?

Dilemma now is to just scrap it or pay for the fix.

Anjobe

High CO means excessively rich fuel/air mixture. According to this web site the most common causes are:
– Defective Oxygen Sensor
– Inoperative Air Injection System (if equipped)
– Leaking or defective Fuel Injectors
– Restricted air filter (especially if high CO is present only at high RPM)
– Vacuum leaks resulting in improper MAP sensor operation
– Defective air mass or air flow sensor
– Malfunctioning fuel evaporation system or purge valve
– Defective Catalytic Converter
– Defective thermostat (cooling system), thermostat stuck open
– Oil contaminated with fuel, excessive miles between oil changes

Kenny Logins

Because Punto?

jolou86

bring it to the car doctor in castledermot.

kingtut

How much would a catalytic converter cost to replace? (Brand new not second hand)