My 06 120hp cdti is randomley being an ass. When maintaining a steady speed (this can be 30mph or 80, doesnt matter) and then putting your foot down, the car hesitates momentarily,splutters a bit then takes off. It is only ocasional and the rest of the time its a dream, full of power with no problem. I have no eml light and after a plug in no codes were found. Anyone any ideas?