I haven't put it onto a BMW diagnostic test yet. I have only been using my local garage, which is not a BMW specialist. I can easily take it to a BMW garage if that would solve the problem.
I will provide an honest answer. I trust this will be appreciated on a saturday. Please remember that a low rating PUNISHES me for being honest and that I receive nothing for my time until a positive rating is clicked.
your symptoms suggest a problem with fuel delivery or mixture, a failed idle valve or air leak
a one hour diagnostic with a trained bmw mechanic with bmw diagnostic equipment will easy find the problem. local garages are not equipped or trained to work on BMWs, and often struggle and waste significant time and money chasing problems.
Please let me know if you have further questions. Please do not forget to CLICK ON a positive rating as this is the only way I receive credit for my answer, thank you. Best wishes with your vehicle.