Maybe it did but you just couldn't hear it. Definitely could hear it as RPM's decreased or at idle once it got a little warm. Here is a pic. If you look closely (darker area) you can see some material covering the upper left side of the opening to the cat. I figure this was my "marble" going around and around as exhaust gas was flowing though it.

I am just glad it is over and the price was right. :tiphat:

I've been hearing a rattling sound too. Symptoms are very similar, rattle is almost nonexistent when first starting up and idling. Normally I notice it when I drive to and from work. Commute is about 30-35 minutes.

If I drive harder in the canyons or on the track, it gets ridiculously loud!

Thanks for finding out what it was. I had my dealer take a look and all they told me was that it was the heat shield expanding and contracting from temperature changes. Bunch of BS. I knew the sound was coming from the exhaust, just couldn't pin point where because that rattling sound carries with the piping. It sounds like it may only be the drivers side cat though

Did they just replace the cat entirely or did they remove the broken material?

I was thinking something like header shield or loose bolt around there. Glad it was fixed :tup:

well I always thought it was just the clutch lol good thing i picked up some fast intentions HFC's should be installing some time this weekend

They replaced the driver side cat. Next time you have the car at the dealer, have them pull the O2 sensor. If it starts to "rain snow" a metallic dust - the converter is coming apart. At that point, they can run a scope up inside and see everything. I was lucky if you will. The scope showed a big piece of mettle laying in the way of the exhaust "flow" if you will - hence my marble sound. See my picture. Pretty cut and dry at that point.

They have to replace the entire cat since once parts/pieces start coming off it is ruined.

Good luck. :tiphat:

Why not? Just get a tune.

That's a rod my friend . I just built my Saleen mustang fully forged and that's what it sound like before I built a new stroked block.

Dude, sorry to burst your bubble but it is not a rod. Since I had the cat replaced, I have run 2 HPD events (just got back from Texas World Speedway tonight after a wonderful weekend) that entails x16 - 25 minutes sessions on track and driven the car to and from both events (roughly 500 miles on the highway) and I have had not problems - or any more noise like a marble rolling around in a washing machine. :tiphat:

Sorry you had rod issues. :shakes head:

BTW - here is just a few laps of one session last weekend with the Nismo. Like I said earlier, I have had 2 weekends of full track time (16 full 25 minutes sessions) and travel time with no issues. I really find it hard to believe you are trying to convince me (because you think something sounds like what you have had in the past) I have a rod issue since I fixed the problem already - a bad cat. Remember not all sounds mean the same thing. :tiphat:

Watch the video - do you really think a bad rod could stand this pressure, :bowrofl:

Cheers.

https://www.youtube.com/watch?v=-FMrIL6jPPc