First thing in the morning or late at night at 80F, or while accelerating, the car decides to make a whistiling (howl) sound as I accelerate even to 20 mph. The howling gets louder as speeds pick up but the RPM is consistent even at freeway speeds. It just been acting up this way noticeable 3 weeks ago and it should not be making this noise on a cold engine or even driving in the first 30 minutes. I've already put a new Oring in the DISA and clean out the MAF with a spray can a few months ago before this howling started , and I can't find any leaks in any of the hoses.
I plan to put in a new air filter early next week but I've already looked into it today to see if anything was obstructing that assembly. Found nothing.
Any ideas? I'm going to have it looked at by my local BMW shop soon.