Opel motor failure 2.0 dtl 82 hp 1997

Hello everyone:

I have a problem in my Opel Diesel Vectra 2.0 16V dtl of 82CV of the year 1997.

It is normally circulating and on several occasions it runs out of power, even if it accelerates thoroughly ... as if it will run out of accelerator ... also when starting in cold the witness is turned on in the engine for a minute or somewhat less, although then it goes out.

Can someone help me?

Thank you very much for the help