had it installed, i dont see why it should throw a code seeing as how the o2 sensors arent even in the catback portion, he has a cai if that matters with these carsDid your friend install it himself or did he go to a shop? all the sensors should be checked to make shure that they are connected and working.
there are no o2 sensors on cat backs. all o2 sensors are on the ypipe and header.Did your friend install it himself or did he go to a shop? all the sensors should be checked to make shure that they are connected and working.