Buzzing Sound from behind Seat or Engine Compartment

[ck]

Hello All,

I am trying to diagnose a problem noise on my 1998 NSX. At a certain RPM range, usually about 3750 to 4250, there is a distinct buzzing sound that seems to be originating in the engine bay. It is most noticeable from the behind the passenger seat. Has anyone every heard of or had this problem? It is like a metallic vibrating sound that will disappear quickly unless the car is in that certain RPM range. It is noisier in lower gears, or when on full throttle.

Thanks,
Chris

 

[jgtcnsx]

might be the catalytic converter. sometimes the heat shield gets loose and makes that vibrating noise