Hi All

A while ago i fitted a K&N induction kit (cone filter type) in place of the standard black box filter on my Signum 2.2 Direct Design 04 plate. When it first went on i had no problems, sounded good, seemed to have more poke etc. About a month after, i had to replace the 'swirl flaps' on the manifold which i'm told is a common fault on signums - i dont think the K&N caused this by the amplified noise made it sound dreadfull. So, new flaps and everything okay for a bit. Two months later and the car seems to be running rough again and alot louder than usual, in fact i can feel the vibrations through the steering wheel slightly. Has anybodt experienced the same thing? Would the K&N be causing this? The car has had a full service not long ago. Any ideas lads?
Cheers