misfire at idle 2.0 tdi 2006 auto

since ive had this car its always had a slight misfire on tickover, recently in starting going into limp mode with a po299 fault with was underboost, i checked the turbo out and the actuator lever wasnt moving at all so i removed the turbo and checked the vanes and freed the lever from carbon build up, its running so much better, ive also changed the injector loom and stripped and cleaned the egr valve, but im still getting a misfire on tickover, the car is a auto so in D its better because the revs are are higher but much more noticable in N.

has anybody had this issue or think of anything else i can check id rather do it myself than send to audi

Thanks

it seems a little better when its warm i think although i tend to leave it in drive most the time so i dont really know, i think i am going to block the egr valve off next and see how i go.