As previously mentioned I have a 2005 MkII Focus, with the 2.0L Duratec HE Engine. I've been having issues with the engine misfiring at low speeds and have tracked it down to the spark plug wells. The wells are full of oil and the O-rings around the spark plug cylinders are dry and cracking so I need to replace them. What I am asking is what valve cover gasket should I buy, and what Spark Plug O-rings should I buy? Any help is appreciated .TIA.