Welsh tez

Hi there I've recently had a problem with my transit which is converted to a ice cream van. Last Sunday I had a problem with my van when I was driving it started to splutter when accelerated. I rev and this problem went away. On Monday it came back with vengeance went I turned the key the engine rev and then cut out went to the garage where they said a lot of problems around the EGR and fuel pump. Both these parts have been replaced and brought brand new. He ran another test after these were fitted and a error code came up p0149 fuel timing error, the mechanic say that it's a new fuel pump so he doesn't understand what caused this? Any help please or advice much appreciated