I have a 1990 560sec 85000 km it surges lightly at 2000 to 2500 rpm (speedcontrol of )i took it in to our local MB dealer they did a complete service ,waist of money it is still the same .It idles perfect ,when eccelerating there is no surge .It surges in all gears at 2000rpm can any one pleeeeeese help thanks bignev