I have a set of O2 sims I used on my Hemi Ram, didnt' work for me but you are welcome to have them. PM me your address if your interested.
What eventually worked on my ram were spark plug anti-foulers spacing the rear o2 sensors out of the exhaust flow a bit.
Heres a link to a better walk through then I could put together.
http://www.mitsubishiforum.com/m_94383/tm.htm
What are the codes? 0420/0430?
My Ram had long tube headers, no cats, dual 3" pipe with glasspacks. LOUD.
Jeff