Mini Countryman jerking and whistling diagnosis

Sounds familiar. I had similar symptoms check engine light, jerking, whistling on my old Peugeot. Have you checked the air intake for any obvious leaks or cracks? A faulty turbo boost sensor can definitely cause those issues, but it's worth ruling out simple things first. Is the intake manifold clean?

Good point about the air intake. I visually inspected it, didn't spot anything obvious. But how thoroughly should I be checking it? Any specific areas that are prone to leaks? And regarding the intake manifold, what exactly am I looking for there?

When I had the issue, the mechanic mentioned that hairline cracks in the intake hoses can be hard to spot with the naked eye. Sometimes, they only open up under pressure. As for the intake manifold, look for excessive carbon buildup or oil residue, which could indicate a leak or other issues. Honestly, with those symptoms, it might be worth getting a diagnostic scan to confirm the sensor and rule out other possibilities. Did you check the sensor's plug? Is it properly connected? Could just be a loose connection. If you have the option I would go to a workshop.

Thanks for the input. Turns out, it was indeed the cable connection to the boost pressure sensor. Replaced it for 95€ and the Countryman is running smoothly again.