I wonder if anyone can help?

After having no problems whatsoever, out of the blue my 2000, 157000mile Citroen Synergie 1.9hdi failed to start. It was diagnosed as a fuel pump problem and it was replaced. Afterwards the idling was lumpy but the car went ok for about 30miles. It then died in mid journey but after switching the ignition off, it started again, drove ok but the engine management light came on. The following day it was not right but whilst taking it to garage, a journey less than 1/2 a mile the light went out. The fault codes have been read and shows 1112. It is still hard to start and lumpy. I find it strange that,with never having a starting problem before, without warning, a pump packs up and now I am getting fault codes which I am told is something to do with diesel pressure. Any ideas on whether this is worth spending more money on?