Engine buzz under load?

[Yury]

I cleaned the MAF sensor and the noise softened noticeably. At this point I barely hear it. I suppose the airflow was undermeasured which resulted in different timing and more air sucked thought the intake.
My mileage was pretty bad too, seems to be improving. I also cleaned the tb a week ago, but that did not change the noise.

anyhow, the engine sounds better. if it was like that when I got the car I would not have payed any attention to it.