Hello all, I've been recently hearing a rattleing sound from underneath my 240 when I start my car, and also while it is in gear at idle .I brought it to my mechanic and he told me my catalytic converter was bad .he showed me the the rattleing noise from the broken pieces inside .My question in this, can a broken catalytic converter cause other problems? For instance the other day my car stalled while I was driving , could it be something in the converter bumping into the oxygen sensor which is located in the cat? Anyway I bought a aftermarket replacement ccatalytic converter from FCPgroton.The make is a Davico.I plan to bolt this one on my self.I would appreciate any information regarding my post .Thanks rf64.