I posted before about a 96 Mustang Cobra I recently purchased with a high idle issue among others. After having my car serviced, I found out that my cats are complete toast. I also had to replace my SC belt and tensioner. After the belt/tensioner replacement, my car dynoed at ~255 rwhp. This is with the 10lb pulley and Anderson powerpipe. I ordered a Magnaflow catted x-pipe (emissions) but am wondering if that would be the cause for a high idle and significant power loss? Here is the dyno sheet. This is a great way to learn how to perform auto maintenance but I feel as though I might have gotten myself in too deep As always, I welcome suggestions from the wealth of information you all have. I may not have responded much but I have read many forum threads and gained what I feel like is a lot of knowledge. Here is a pic. Still a good looking car with a powerful sound...just not a whole lot of go Thanks for your help!!