Hello, I have 316ti with N42 engine, and by what I read you seem to have had similar idle problems as I do. I am new to this site, so I have not read through all the topics, but I'd like to ask if you have managed to solve the problem, and if you have, what has worked?
Also I found on Youtube a video of idle problem that seems exactly the same as I have (sometimes the rpms start to slowly rise and then rapidly drop without a reason, sometimes the rpms sail between around 650rpm and 800rpm while the car stars to shake):
http://www.youtube.com/watch?v=F4VqnsqbKas
(the video shows both, though the latter isn't that noticable on the video)
Any thoughts or tips would be appreciated.