wallyp

Sometimes you can hit the cat with a rubber or dead-blow hammer to see if it rattles.

Jan Cilek

I went without trouble, emissions within OK range, without two rear carbs

eldos1

A common thing from the import tuner world is to have the cats installed with a flange on each side and have them sell you a straight "Test pipe" for ummm.... Dyno Testing This makes an easy swap.

drchadneeld

I know this is a super old thread but I am having the same rattling on my 2005 S500. When you went to straight pipe, you didn't have any computer codes or any problems? Also, no loud exhaust noise?
Thanks for the help

Marke525

I have the right side going out (probably soon to be followed by the left) The mechanic I was talking too side it would be difficult to fit universal's. Does anyone know if this is true. I'm considering using the Walker 82503 and 82600 units. Is there anything unusual about the OEM units? From the earlier posts, there doens't seem to be an issue. I am in California though.