OK so I have had my 2001 Integra LS for about 9 months and just a few weeks ago I started to hear a metal scratching noise coming from the engine(maybe tranny) at around 3200 RPM. Very rarely it will do it at 4500RPM and beyond that I don't really notice it. Any ideas on what the problem is and/or how to fix it???

 

Possibly rattling heat shield. Get under the car and take a peek at the heat shield on your cat.

 

x2. A while back I noticed my car making odd sounds at certain rpms, so i was afraid it was something mechanical... but it was only a rattling heatshield.

 

It could be your cat coming apart too on the inside if you still have factory exhaust

 

I took a quick peek at the heat shield today and didn't see anything that looked out of place. Also I checked the cat a little bit and everything looked good there as well. It sounds like its coming from the front left of the engine it self. ideas?