I recently installed a stage 2 clutch in my 03 get coupe. The clutch acts as it should except when at idle, sitting in traffic right after I had the clutch installed I noticed a shuttering/rattling noise when the car was in neutral. When I press in the clutch the noise stops so I know it's from the clutch. Does anyone know what's going on??

 

Stock flywheel?

 

You failed to read the many posts on replacing a clutch using non OEM parts.

Telcoman

 

Sounds to me like a throw out bearing issue, that will make the exact sound you described. Aftermarket clutches can be noisier than the OEMs.