Ford Repair: P0430 CEL Error Code, catalytic convertors, oxygen sensors

Question
Hello Mark,

I have a 2007 V6 mustang with 11,000 miles. I changed the stock headers about a month ago and installed the Ford Racing Dual exhaust. In the process, I had to unplug the spark plug cables. When I put it all back together, I accidentally plugged the last three in the incorrect order. Instead of 4, 5, 6, I plugged them in as 5, 4, 6. I reodered the correctly and my car has worked well after that. About three days ago, I went to fill up my car with gas and on the way home it was hot outside, about 90 degrees. I am about 30 feet from home and the CEL light comes on. I pull the code and it comes out with P0430 - Catalyst System Efficiency below Limit - Bank No 2. Could it be anything that I did to the car? Also, the car is a bit rougher than before on acceleration. I reset the code and I was able to drive around for a while before it came back. What would you recommend? I was thinking of first changing out the spark plugs to see if that makes a differences. Any help is greatly appreciated. Thanks!

Answer
i don't get into much racing changes so did you remove catalytic convertors or oxygen sensors what sets that code is when the rear oxygen sensor on bank two isn't seeing enough of a change in exhaust content from when the exhaust enters convertor to when it exits convertor usually a bad sensor but if it is a convertor it is under warranty as long as anything you changec did not void it. crossing wires for a short period should not have hurt convertor that quick as far as running rougher if your wires are ok and you didn't get duped into using splitfires,champion or bosch plugs if you didn't crack a plug you should be ok. but you better check the plugs because one misfiring regularly can damage convertor.