Are my symptoms typical of a bad CAT converter or ECM?

Question

My '00 max gave code P0420.  When cold, engine is very rough and wants to cut off.  When warmed it runs perfectly.  Has anyone experienced  same symptoms?  What is going on with my Max

Answer 1

Code P0420 means that there is a problem the the catalytic converter system. If the catalytic is coming a apart it may caused the engine to stall, otherwise the running rough may be caused by something else.