@T5-T6-Schnappi thanks for the reply. No oil consumption at all. The car is from USA. The car is stock. The car is at ~180k kilometers.

I had the cat inspected by a probe and it's not melted/damaged. I was getting and error P0420 and no others If I remember it correctly. I had o2 sensor check and it was working fine, it graph from it wasn't steady. So we added a spacer on the o2 sensor. It "solved" the P0420 error, but now I'm sometimes getting another error related to the o2 sensor. That it's stuck on lean.

The error code wasn't constant, it sometimes appeared when I did longer trips with harder acceleration on the highway. Same as the stuck lean error.

Hello,

I just got an error code for low efficiency of catalytic converter. 1/4-1/3 of the cars price. So I was looking if it's possible to disable this check of lower the threshold so I do not get this error message? The error code appears and cleans itself intermittently. The car is a Petrol T6, so no aftermarket catalytic converters I could find exist.