Help

Hi guys I'm new I have a audi a3 2.0tdi quattro 170 16v it's the 8p  iv ownd it for a couple of months now and had to put some major work into it the guy I got it off had the head rebuilt as the cam belt snapped last year it runns mint tbh for the milage it's had an egr delete and a dpf delete and I had it mapped yesterday power is amazing the issues I'm having is lumpy cold starts and it seams to be a bit tappy until warm iv been reading forums about setting up timing on pd engines and also the lash clearance on the injectors it's sort of sounds like it missed a tooth on timing until its warm could in be tappets could anyone shed some light hope I opened this in the right place