Recently, the code P0420 came on. I have problems with my car vibrating at the stop light when I'm braking. It starts running normally again when it is in neutral or when I speed up. There are no changes in fuel economy. I think this shaking has to do with the error code. It indicates issues with a possible leak, the catalytic converter, sensors. Please give me some advice on what to do as I would like to know more about this code and my car shaking. Thank you in advance.
If it was the converter, then you would typically have a loss of fuel mileage and engine power. If you do not have those, then it may be a sensor. I typically start by installing a scan tool and monitoring the oxygen sensor signals as that will let me know if the sensors are failing. If you plan on having this repaired, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose and repair your car’s Check Engine Light and shaking issue.