Trying to diagnose an exhaust rattle. I seem to remember it when i had a TP/HKS dual exhaust and now that I've put the stock OEM cat/exhaust back on its louder. It sounds like it's coming from the cat. From my most recent install the tip of the O2 sensor looked fine and i don't recall the cat rattling when I was carrying it/installing it. Checked all bolts just now, nothing was loose, hangers were fine.

Don't mean to be hasty and post up a "HELP ME ASAP" thread but I figured others could use it as reference for diagnosing their own cars as well.

The rattle mostly happens at idle but you can hear it around 2500-300 when revving the car as well. It sounds like a bolt is loose but i tightened up all the bolts as well as the O2 sensor bung.

Next step is to replace the cat with my old Berk 63mm test pipe and see what happens. Too dark out now to do it tonight.

http://www.youtube.com/watch?v=rthq8r1XRVI

 

I had the same problem. Check to see if the honeycombs on ur cat have come loose. If so, some pieces may have broke off and is what is causing the rattle. May wanna change it out. Eventually they honeycombs move so much they shear off your secondary o2 sensor $$. Jm2¢. Gl.

 

appreciate the input, definitely going to put my test pipe back on with the OEM exhaust and see if the rattle goes away.

should also mention the car has 70k on it but i've had a test pipe on for at least 20k+ miles, so the cat definitely hasnt seen 100k or anything.

 

For some reason s2k catalytic converter's are notorious for going bad. My second one went after the first one was replaced under warranty.

 

Must be the OEM cat, put the test pipe on, no rattle.

I shook the cat and i didn't hear anything loose and the heatshield on it seems fine.

Also - the gasket between the cat and the exhaust was fried to bits, so i put the test pipe on without one between it and the exhaust, sounds fine for the time being until i can order one and put it back in.

Thanks for the help, hopefully others can use this as a reference as well.