i also have this type of noise but it seems that the car will do it when it pleaes cuz i can go days w/o it doing it. its also like a noice as if letting air out of a baloon. but mine will do it when it idles cuz i like if i rev it a tad it will go away but then as soon as i let off the gas and it goes into idle it may do it again. i also had someone turn it off and stuck my head under the hood and it came from around the same areas as mentioned earlier. i was going to change belts but since it didnt seem to work for AIRBOY. the car only has 34K miles hmmmmm im kinda stuck on this also
Hmm...sounds alot like what my car is doing...if it idles long enough it'd become a contiuous noise. Rev the engine just a little and it goes away until the RPM settles again. With 34k miles you should take it to the dealer to have them look at it. If you do, please post the results.
Sunny