2001 honda ac. With code p0420 and cat replaced not to long ago wut could be the cause

Question

Would it be a bad cat?or bad o2 sensor?

Answer 1

Hi there,

You could have an issue with poor running, poor quality of fuel, bad rear O2 sensor or an issue with an exhaust leak. All of these can cause the code without the converter actually being the problem. If you used an aftermarket converter, it could be the cause as well.