Been having this noise for the past couple of weeks . At first looked like its coming from the passenger side, now looks like it's coming from bottom. I also Have the SES code P0420. You think might be the pre-cat making this noise?

In addition, Been having this noise for the past couple of months. Sounds like the fan hitting something but noise not coming from fan. Look like coming from cats?

knocking/rattle noise at idle:


And when turning off the car:



Thinking of gutting the pre cat, or replace, whichever one comes cheaper

 

I have the same exact rattling from my engine bay somewhere and have not been able to figure out where for years. I also hear the engine bay rattle when turning hard to the left, sometimes while accelerating, and when I turn off the engine just like your videos.

I just recently found out one of my motor mounts are bad. Im gonna get that replaced and hopefully my noise will go away.

 

After lifting the car, pinned the sound to the pre-cat (the bank 1 closest to the firewall). Taking pre-cat out, sure enough piece of the honeycomb mesh came out. Will be replacing the pre-cat, now the question is which aftermarket to get (wont be guttin the cat, & OEM cat $810!!!). Looking to get this, unless anyone recommends some other brand...?

• EASTERN CATALYTIC Part # 40477 $177.79 (Rockauto) http://www.rockauto.com/catalog/more...630&cc=1431961

 

I've been having the same issue lately. How did it work out with the 40477? Was it a simple drop-in replacement or did you have to make any changes?