Hi, posting this here for anyone who might find it helpful.

Problem:
Over the last six months, I had a rattling sound coming from beneath the car, between the driver and passenger doors. A lot of posts on here and elsewhere pointed towards the catalytic converters as the source of the problem, and I was fearing the worst as they are very expensive. The video at night gives a decent demonstration of the rattling noise as I pull out.

Solution:
I finally got the issue fixed when I had a bunch of work done last week. It turns out that the issue was a perforated Y-pipe, which I had not thought to look for oddly. Ended up having my mechanic get an OEM-style replacement part and the noise is gone! The daytime picture and video show the final results.

I hope this was helpful!

Additional Notes:
- I also got new Centric Premium rotors all around after seeing several recommendations on this forum - they are amazing, I strongly encourage them!
- Yes, I put "3.7" fender badges on my car and I like them.

 

thanks etw, but I swear, I can't hear a rattle in the before sound clip...

I'm fighting a rattle on my own, one mechanic thinks it's the exhaust VVT, dealer thought it was a heat shield on cat; strapped cat down, sound helped but didn't disappear. I wonder if mine isn't the cat coming loose inside. VVT on exhaust is built into the head...so oops.

 

Yes, the rattle might be a little difficult to distinguish from the video, but unfortunately I don’t have a better video from when I had the issue.

If the rattle was coming from the exhaust VVT I assume you’d probably be able to hear it most clearly from the engine bay.

The heat shields around the Y-pipe were one of the first things I had to fix when I bought my car. Most of the nuts, bolts, and clamps holding them on were rusted so that might be a good place to start, especially if you’re able to knock them loose by hand. I would give that a try if you haven’t already.

Other than that, my suggestion would be to take off the heat shields and check for any issues or to remove the Y-pipe and inspect the cats. Best of luck!

 

thanks etw. I just had it back to the Nissan dealer (who sold it to me) and they diagnosed it with the cat rattling inside. Looking hard at some high flow cats (their quote was $1800 for one cat and an 02 sensor, good grief)