What is PUTI?

Hello everyone! From my questions you probably noticed that I’m looking for an omi, and that I have no idea. Soon it’s over. At the weekend at the latest I have to buy en. (Then there are certainly other questions :-)) Well, I found again an offer – I think – 2.5 TD (131PS) BJ 12/94 ; 154tkm. pretty well equipped. The seller said that it reacts badly to the gas in the cold condition and about 2 – 3 min. after the start can be quite no In addition, he told me about some device for gas control and called a name PUTI. Could anyone please explain to me what this is about, and how expensive would any repair be? In advance thank you