I have a 02 Honda civic i changed the Catalytic Converter on it for a performance one but now the engine light stays on and the engine code is low catalytic efcisony.Is their some thing i can do with the ecm or something to by pass this to take the code off.  

you need a defouler for your O2 sensor  

where can i find this at or can i go to the local parts store to get this.  

thanks