I've noticed that rarely when I start the engine, my 2001 530i starts vibrating. If I turn off the engine and restart it, vibration stops. Today I it vibrated again and I even saw the "Service Engine Soon" light came up. Again, the restart solved the problem. This happens very rarely. I called the dealership and they said that they probably won't be able to reproduce it since it happens rarely and suggested that I just bring it at the time of the next scheduled mainetenance. Has anyone experienced anything like that or heard anything about it? Thanks.