Mercedes: check engine light issues, universal converters, o2 sensors

Question
I have a 2001 benz e320 chassis 210, engine 112.941 with emissions problems. I had codes for purge valve,charcoal cannister, fuel sender and o2 sensors. changed all except o2 sensors. I no longer get any of  these codes and the car does not have any driving problems. Now I am getting codes po422 and po432 (main catalyst efficiency below threshold banks 1 & 2). Where do I go from here? Please dealership not an option.

Answer
Tracy,
You probably have a bad catalytic converter. There are after market converters out there at huge discount over dealer equipment. If you take the vehicle to an emission shop they will confirm a bad converter.
I would locate a local muffler shop and find out what they would charge to install a customer supplied converter.
here is one site that offers universal converters for less that 50.00.

http://www.racepages.com/products/?D=catalytic+converter&Ntt=catalytic+converter...

Good Luck
Rob