When started it runs fine idles fine even boosts fine but is knocking at the same speed it sounds like its coming from the back of the engine. As I say it starts fine so could it be the starter not disengaging? Or am I up sh1t street and the engines buggerd? It went away for a bit then came back with avengence. The 5 is now in the garage. And staying there as Iv had enough of it for now.. Anyone had the same?