engine noise / oil in throttlebody.

i have a question or two for a friend of mine..

2002 Cougar C2, 2.5v6 auto.


- is it normal for the engine, whether idle or not, to have a somewhat
buzzing sound? Buzzing is the best word i can think of now. to me, it
sounds close to the sound of when a powersteering pump is bad.. but
it doesnt have any other symptoms.. its never worse or louder when
turning or if the wheel is cut all the way.. it seems normal, but we're
both curious?


- secondly, we went to change the air filter.. and i had noticed
there seems to be engine oil laying in the throttle bottle ridges.
i've never encountered anything like this before, so i was totally
clueless.



any help is appreciated!


thanks.