I had a new cat fitted as old one broke inside, it's just a cheap one from a motor factor, from the moment it's been fitted, not all the time but most of the time. When slowing down under engine braking it's not slowing down as much as it should or at all really and when it's doing this it idles very high aswell and is jerky. The traction control light has also started to come on when it does this. It's starting to really irritate me! Any ideas as to what the problem is? 1.9 m44 engine
