Last Saturday I picked up my new 2008 EX Atomic Blue Coupe (5sp Manual). Ever since that day, I'd heard a very loud and annoying dashboard (or so I thought) vibration.
Today, while looking for the offending sound, I happened to move my head forward and to the center of the dash while I was driving. The dashboard is quiet as a church mouse - it was coming from the "A" pillar (I guess it's the "A" pillar - closest to the driver). Started banging on the pillar trying to get it to stop. Happened to put my hand on my.....wait for it.....my....garage door opener attached to the driver's visor, and the vibration stopped. The freaking clip on the back of my garage door opener was loose and was smacking the plastic back of the visor. GEEEEZ - what a dumba$$. I spent a week looking for this and was ready to start pointing fingers at Honda, based on the last Civic I had (1996 - MANY sounds- creaking, vibrating, etc.).
The problem in trying to isolate the noise is one of sound propagation. That huge cove created by the acre-plus size of the windshield and dashboard can create some very misleading clues about noises. Trick was to move my head as far forward and to the center as I could safely do while driving. Once I did that, I couldn't hear a peep out of the dash - all noise was coming from the right and up - leading up the "A" pillar to the visor and my opener.
I'm such a loser