Polo 1.4 Tdi possible misfire

[reece_]

Hey everyone , need some advice with my half broken polo. Sounds terrible like its spun a bearing but I believe its diesel misfire. Now it started randomly one week where the first 5 minutes of driving were rough then as it warned up it becomes normal , no limp mode and full boost etc. Now its gotton alot worse where its like it all the time , however there are random days where it goes back completely normal and fine. Which leads me to think its more injector/ fuel related rather than sticky valves etc. I recentley cleaned the egr valve etc but its had no success. There are no codes or lights on. Any advice on where to start or what this could be really appreciated thank you !