Guys i'm getting a funny noise from my exhaust and I'm trying to figure out what it is.

I don't know how to explain it, but it only comes when I first step on the gas and then everything sounds normal. When I press down on the gas on like 3rd gear doing ~40km I get a low rumble (sounds like a V8) for a sec or two and then goes away.

I've looked under the car today and everything seems fine, no dents or loose joints so I'm guessing there's something loose in the cats but I'm not sure.

So basically what are the symptoms of a sport cat going bad?

 

same exact noise here. I think it's normal. I dunno though. Wait when did you get cats? I have invidia hfc's with stillen catback, so i can here every little detail pretty well LOL

 

well I installed my cats in May 2009 and installed my invidia exhaust in Oct 2009.

The noise I'm talking about has only come up over the last week, I'll see if it changes in anyway

 

is it possible to make a recording of it?

 

humm, it'll be very hard to get a clear recording of it tbh (it only lasts for 1-2 sec max) I'll see if I can get anything.