I have a 2000 Mercury Mystique comes up on the OBD II code p0420 Catalyst system efficiency for bank one is below threshold. I just had the convertor replaced two weeks ago, and the check engine light came on yesterday. Anyone know if it could be the 02 sensor behind the convertor?? PLEASE HELP!!! I am getting about 100 miles to a tank of gas........
- posted
17 years ago