Heard it for the first time last week. Put the car up on jacks to try to pinpoint the source but no luck getting any sound. Pretty loud but infrequent and happens on decel only. Any ideas? I'm stumped but I'm no mechanic either. Thanks.

 

Although you have an '04, I believe you have the clutch decel "buzz". This was most prevalent on the earlier models but other years have been known to do this also. It's just a noise and has no detrimental affect on the mechanics of the car. The clutch springs start to vibrate on deceleration at a certain rpm.

 

Just reporting back in on my findings...

Put the s2k on a lift today (thank you Curt at C&C) and noticed discoloration under the undercarriage just above the front weld from the resonatorectomy. Good evidence of a leak. A quick trip to Meineke for the stethoscope test confirmed a pinhole leak. Meineke touched up the weld and had me back out the door in 15 minutes.

The sound from the exhaust had increased noticeably and rapidly. It is now back to the levels I recall previously so I'm pretty sure this fixed the problem.

Have a great weekend.

 

Glad is wasn't your clutch.

 

it could be ur exhaust tapping somewhere.