My car runs fine but when I come to a stop my idle drops and sometimes dies.

Question

P0420 code came on and I changed both 02 sensors and my car is running the same.  When I come to a stop my idle drops and all my lights come on and wants to die.  Not sure what my problem is ???? any ideas???

Answer 1

Hi there,

first, this code is for a bad catalytic converter. Even though you changed the O2 sensors, if you are still getting this code it does indicate there is a problem with the converter.

Second, you may have a faulty mass air flow sensor. Sometimes when they fail it will cause the car to stall because the computer doesn't make the right fuel mixture.