hi i have a 2008 (58) new shape c5 tourer dw10bted4 im having trouble with the car having a flat spot randomly below 3000 rpm .also the car can cut out in traffic but starts straight back up. There is no eml on but there is a intermittent code of p2562 ,which I believe is turbo under boost? I have checked all vacuum pipes and intercooler pipes ,changed the pierburg vac solenoid to the turbo .removed and cleaned the dpf filter.i carried out an injector leak off test and all looked even. im just about out of ideas anyone help ?