So not to long ago I noticed a weird grunt like noise coming from my Protege and I have no idea what it could be. When Im idling it will grunt a few times every once in a while and my RPMs will raise about 100 or so rpm.
Has this happened to anyone else here?

Edit: Its a 2001 mazda protege ES
heres a video so you can hear it for yourself:
http://www.youtube.com/watch?v=4dsmtnHwDJw&feature=youtu.be (Just uploaded so if it doesnt work now it might still be loading)

Any help is appreciated

well i hear it. sounds like perhaps a vacuum leak? but only occasionally?

Yeah thats kinda what i was thinking but i dont know why it would only be every once and a while