surging

Hi our 2004 td4 begins to surge at all speeds after about 4000-5000km after servicing,took back to land rover dealer they could not fault. progressively got worse. Drained oil again at home it had 7ltrs come out and does not blow any smoke turbo was replaced two months ago after the old one emptied the sump. After oil change all good no surging and performing well. Going to monitor again this has been going on since this engine was installed in 2009.Has anybody has this occur. also sending oil sample to the lab for its condition. cheers rob

Ermmmm as I understand it, and I do my own oil change, the engine should only hold about 6.5ltr max. Sounds like yr servicing place put 6.5 in without checking level after 6!