Engine shaking...

[classyceta]

So I started to notice that while stopped at a light, the vibe (09GT) started to make a sound, best way to describe is a low howl/vibrating sound. Once I throw it in NUETRAL or when i drive it goes away. So I asked my wife to put the vibe in drive while I opened up the hood and I noticed the car shaking a bit more then normal, especially the air box. So I held it down and my wife told me that the noise is gone. Did that a few times to make sure and sure as hell it stopped when pressure was applied on the air box.

Any idea what that could be? A loose/missing screw? Tranny mounts shot? Etc....I don't know what to look for. Thanks!

[trb]

The airbox is held down by a couple of bolts under the filter, so maybe they have worked loose or something.