Would be greatful for any help. I have a 06 focus st3, had it serviced recently(new plugs,oil,oil filter)but noticed that it has developed a shudder when accelerating hard in gears at about 3500-4000 rpm at peak boost more noticable under load when there is three people in the car. It also feels like it has lost some torque. I also have a Graham Goode induction kit which i have cleaned myself with a K&N filter cleaning kit and the car was remapped approx 1 year ago, car has 54k on the clock. Any suggestions would be much appreciated.