Mini Cabrio Cylinder Pressure Fluctuations

Fluctuating cylinder pressure on your Mini Cabrio could stem from a few things. Have you checked for any obvious vacuum leaks? Also, when was the last time you replaced your spark plugs? A faulty fuel injector could also cause this, though I'm not sure how likely that is. It might be worth checking the condition of your timing belt as well, though I am not sure that would cause this.

Thanks for the suggestions! I haven't checked for vacuum leaks yet, I'll try to do that first. Regarding the spark plugs and timing belt, how would those cause cylinder pressure issues exactly? I'm not that knowledgeable about the mechanical details, so any further explanation would be greatly appreciated!

Okay, I see. It’s difficult to say exactly what is going on without looking at the car. Spark plugs, if worn, would cause incomplete combustion, leading to pressure differences. A timing belt issue could affect valve timing, which impacts cylinder pressure, but it isn't the first thing I would check. However, considering everything, it probably would be best to get it checked out at a reputable workshop.

I wanted to report back that the issue is now resolved. It turned out to be a vacuum hose leak, which the mechanic fixed quickly. The cylinder pressure fluctuations were a knock-on effect, as suspected. The repair was free since it was a minor fix during the inspection. Thanks a lot for your help!