I just bought a '96 GSR 5spd with 120k on it. There is a metallic buzzing noise coming from the front of the engine. It happens lightly at 1500 and much louder at 3000 rpm. It's very rpm specific and only lasts about 100rpm. It does it either driving or sitting in the garage.
The car had a head gasket and valve job at 110k done by an Acura dealership.
It had a new water pump and timing belt at the same time.
There don't seem to be any loose heat shields or hoses or anything. It really sounds like it's coming from the area of the timing belt cover. Anybody else run across anything like this?
Thanks for any info.
I've also got some questions about cold start idle speeds that I'll save for another post.

 

i had the same exact problem...never figued it out cuz it just went away...bump for this guy...its really annoying..

 

I kinda suspect the timing belt tension spring but don't really want to tear the covers off without some moral support.
Did you just have a timing belt put on or anything?