Just for anybody that is expierencing this same rough idle problem. Once the car warmed up it idled rough and knocked. Very embarrasing sitting at a traffic light. The knock sounded like it was coming from a loose heat shield on the cat. I pulled the cats off and the passenger side was completely hollow, no honeycomb. The driver side had one loose honeycomb and one solid. I hollowed it out and put them back on. Then I reset the ecm by disconnecting the neg battery post. It now runs perfect and no knock. The cat innards must have beat themselves to dust once they loosened up.