2007 Mazda CX7 Troubleshooting Engine Noise

I recently just purchased a used 2007 CX-7. I'm now at almost 68K miles and the engine makes a noise that I can only hear at idle. It sounds for a lack of better words, like a "flapping" noise. The noise comes from the passenger side of the engine. When starting up first thing in the morning the sound isn't that audible but as it's driven (warms up I guess) the noise becomes louder. When I drive it, the engine still has pick up and does not show any lag.

I've looked under the hood and have isolated it to the engine area maybe on the side somewhere but can't figure it out past that. I know that over time 4 cyls tend to get loose and have that kind of sound (what I call the "butterfly" effect). Does this sound like that or something else I should be concerned with?

Here's a video with the noise: http://www.youtube.com/watch?v=DAazssstmQA

If it is only wear, is there anything I can do to help ease the noise?

I make sure I use premium....and I'm contemplating changing the oil just in case it'd been a while since the last...do you think this may help?? Or do you think it might be a belt of sorts?

Thanks for any help!