Having this issue with a rattle/knocking/pinging sound. been going on for a couple thousand miles, isn't getting any better or any worse. I've searched the forums but I can find one that's the same or with a solution. The rattle happens at idle to about 2200rpms and then it goes away. the video is pretty much right under the driver's side cat while I rev it to about 2k. The sound doesn't seem to be coming from under the hood, just under the engine, I can't even hear it under the hood. sounds like a popping/knocking sound. Does anyone have the same problem or know what it is and the solution? https://www.youtube.com/watch?v=5lAKtvRF3VY&feature=youtu.be (wait until the car is revved a little in the video, you will hear the sound quite easily)

 

I believe I have the same rattle (haven't yet found a fix). Do you have aftermarket cats? Or any aftermarket exhaust components?

 

Sounds very scary. Im in no way an expert at diagnosing so ill refrain. But doesnt sound good. Weird is at idle that sounds healthy normal then gets weird.

 

Your cats are loose - My friend's coupe had the same noise

Get this on the lift and you will figure it out

 

That's interesting. I have yet to hear another G with that exact noise, all I can find is the muffle problem with the spot welds breaking (but I have a muffler delete and it's still there) I'll definitely look into that, thank you!

 

UPDATE:
It is indeed the catalytic converter. the material inside broke and that is what the rattling sound is. will be replacing it very soon.

 

Is there a TSB regarding this issue?

Anyone know if there are legit aftermarket CATS that are CARB and california compliant? I have the same issue on my 09 with 150k.