Mini Cabrio running unevenly

Uneven running and jerking? Sounds familiar! I had a similar issue with my Mini Cabrio a while back. Have you checked the oxygen sensor? A faulty sensor can definitely cause those symptoms, as it messes with the air-fuel mixture. Also, when was the last time you replaced your spark plugs or air filter? Those are relatively easy and inexpensive things to check first.

Oxygen sensor, okay. Where exactly is that located, and how difficult is it to replace? Spark plugs and air filter are fairly new, so I don't think that's the issue. Could it be something with the fuel pump maybe?

The oxygen sensor is located in the exhaust system, before and after the catalytic converter. Replacing it yourself is possible, but it can be tricky depending on how corroded it is. Given the error code and your suspicion of an exhaust leak, I would lean towards that being the primary cause. An exhaust leak can throw off the oxygen sensor readings and cause the engine to run poorly. While a fuel pump issue is possible, it usually presents with more severe symptoms. My advice would be to take it to a workshop and have them check the exhaust system for leaks. They can also properly diagnose the error code and pinpoint the exact problem.

Just wanted to give a quick update. It was indeed a leak in the exhaust system. They replaced a part, and the engine runs smoothly now. Total cost was 265€. Thanks again for your help!