Having a quick look just now at my car, I could feel an air leak on the PCV plate. The hose on the right of this picture has an air leak, and if you place you finger near the base of the hose where it enters the PCV, you can actually feel it being sucked in ( when a few mm above the leak, that is ) to plug the leak. The pipe seems to go onto the end of the fuel rail, so would this be a likely cause of the rough running,or does anyone know what this pipe is doing ?

Cheers