Focus ST170 Misfiring
Pretty new to the ST world and have picked myself up a tidy looking 2003 Focus ST170. the car is as i had hoped except one thing. A terrible Misfire. This issue seems to be when I accelerate and as the engine is faced with a greater demand for power (as the revs build past 4000 rpm) the engine seems to really struggle and misfire. This is so disappointing because I can only imagine how quick the car can be and not actually feel it. Even more so as this is my second car and the one I planned to do a few track days in this summer. The misfiring seems to also occur, although less frequently at lower revs in 4th and 5th gear when you accelerate.
I will be checking the spark plugs this week and I am dubious as to whether its the Injector cylinder (the long thin cylinder and the back of the bulk head. But these are both theories and having done 115000 miles I am very worried I require an engine rebuild!
ANY HELP would be massively appreciated.
Thanks