Renaul Trafic van lost power and stopped?

Hi, I have ''59'' plate renault trafic 9 seater van which was running well. one day I lost power and engine and coil light came out. Tried to start again but no joy. Called the AA and found out to be fuel preasure controller failed. Took it to renault garage and its more than three weeks no joy. They have put a new pump and injectors and now it will start and then stop.
The dealears havent found the problem yet and the vehicle is still out of order. Can anyone please help me.