Just recently I started hearing a rattling noise coming from the back of the car. It happens when I accelerate and cant hear it while driving. I have a Nismo exhaust on, is there anything that could be hitting in the rear that I should check? Any help is appreciated cause the noise is starting to get annoying.

 

I'd crawl under and have a look at your clearance around the exhaust

 

I just installed hfc's and I hear a buzzing/rattling sound sometimes when i accelerate. is this normal?

 

the rattling noise that you hear near the back end of the exhaust, get under the car, and put rubber washers near the part that touches the under rail of the car.. give it a shot...

 

+1

 

what part is that? is it part of the exhaust or the cats?