Thank you. The p0420 code has come on then gone then come on again. We are trying the upstream o2 sensor to start. Hope that fixes or helps. Once all said an done this thing will drive like it’s new. Some of these codes are being read on the code reader with no check engine light on. To night we taped the o2 sensor ( was changing it but had wrong socket) the car coughed and ran slightly bette, and noises were gone. Fingers crossed this works. tomorrow.