Hi guys,
My 05 special edition with 122k miles has literally caused me 0 issues since brand new, until now. It still drives normal with no smoke but I'm afraid something is about to give.

I had noticed a fainter version of the grinding noise starting wednesday. By friday it was pronounced and I realized it wasn't just me - something from the bay was grinding/rattling loudly upon throttle lift off. I parked the car at home but left it running, using the throttle body to manipulate the revs (instead of the gas pedal). 3 out of 3 times there was a loud grinding/rattling noise from the engine area for about a full second after I'd let go of the TB close. If i hold the gas steady there is no noise, even at higher rpms. All fluids look good and are at proper levels.

All regular maintenance has been completed, especially related to the motor/transmission. Full T-belt/wp job completed at 109k miles w/ transmission fluid change using honda fluid, I checked the valves at 115k miles and they were all very close to perfect and did not need adjustment.

I'm no mechanic but from my understanding since it makes the noise while in park, the drive train after the engine is not suspect (transmission, axle, etc.). I've heard engines when their internals are about to fail and this doesn't seem to match the symptoms or noise. I double checked the pulleys but there is nothing obviously wrong with them (loose etc.).

Any suggestions guys? Don't mind riding the RC51 to work and school but I wear slacks/half suit and would rather avoid having them soaked in sweat in 5pm traffic if possible.

 

Videos
http://www.youtube.com/watch?v=KeljzeedVY4
http://www.youtube.com/watch?v=AjHGLCp4hhE