Galaxy 1.9 Tdi Lumpy From Cold Start?

[smoggy7]

hi, i have a galaxy 1.9 tdi on starting from cold in the mornings i get this lumpy sound coming from the engine, i have just had the filters changed , and oil change but it only happens when cold ie morning start, it is hard to describe the feeling i am getting from inside the car but it is lumpy and noisey for about 2 -3 mins then it goes all day with no problem star6ts first time after stopping, soon as i leave it over night when cold start the engine and its like a very heavy thumping noise that lasts only mins plz can someone advise on what they think it is , ive been told of a few things belt tensioner, or the sound in desiels are a bit noisey many thanks smoggy7