Blackbird

I am getting catalyst below efficiency codes and I know the 02 sensors are good. I popped the exhaust off and looked at the cats best I could. They are not melted, chunks missing, etc...

My question is if the cats are in some sort of state to set off the code are they costing me power? or if they appear to be in good shape visually I am ok power wise?

kbronSS

I had my cats replaced at a GM dealership for free.....they are under emissions warranty for like 60k miles or so. But if i were u, i would just take them out and forget about them. And YES, they are prob robbing u of power. Once mine were replaced, the car acted a lot better and u could hear the muffler more.