Van wont start ???

Hi i have given my van a new battery, alternator , breaks, full service, and it was driving perfect, it lost power while driving on the motor way and would drive over 10k a hour and wouldn't rev ??? next morning it was driving perfect and was great for 2 week then it started getting jumpy and was losing power again. I came out next morning and it wouldnt start she is will turn and have full power and i have all light on dash, no warning light she just wont start, ??? has anyone got an idea's its a 04 vivaro 1'9tdi PLEASE.