Mini Cabrio engine running rich

That does sound quite similar to an issue I experienced with my Mini Cabrio. Reduced power and rough running were the main symptoms. The check engine light also illuminated. Have you checked the air filter? A clogged filter can affect the air-fuel ratio and cause the engine to run rich.

Thanks for the quick reply. I did replace the air filter recently, so I don't think that's the problem. However, you mentioned air-fuel ratio. Could a problem with the intake manifold also cause a rich running condition? I've noticed some jerking when accelerating, and my fuel economy has taken a hit.

Yes, a problem with the intake manifold can certainly contribute to a rich running condition, but the jerking and poor fuel economy strongly suggest an issue with the fuel injectors themselves. It sounds like your engine is getting too much fuel, like trying to drink from a firehose. It's worth getting it properly diagnosed by a mechanic, as driving with a rich running engine can cause further damage. I would recommend taking it to a workshop.

Just wanted to give you an update. I took the Mini to a mechanic, and you were spot on! It was indeed a faulty fuel injector. All injectors were replaced, and now the engine runs smoothly again. Repair cost 515€. Thanks a lot for your help!