Break like noise from engine and rough idle

What is your question?

My 2008 BMW X3 has a noise from the engine that sounds like squealing breaks but it is constant. There is also a rough idle that my car has. And finally I have 5-6 lights on in my car including the service engine soon. All of these symptoms happen when my car drops rpm's rapidly, down to below 500. Can anyone help?

What makes this problem better or worse?

Driving for a while

How long has your 2008 BMW X3 had this problem?

A few months