2.5tdi AKE idle/engine running uncommon problem

2001 Audi A6 C5 2.5TDI AKE quattro 6sp 27,000km NO CODES

inector pump died. codes like 00550 and more, but it started nicely and then jumped revs. was undrivable.
changed it to another (drove that before car so it was fine) but the engine was BAU or AFB dont recall.

had problems with that, the electronic unit ontop the pump was not working with my car very well. so i swapped that part of the pump with my old one from the broken pump.

bled it and it started fine, checked with vcds and tdi graph was fine.
set timing perfectly with vcds.
no fault codes.

no vcds used to bond anything, just exchanged the housing of pump.

then i noticed when the car is below its working temperature (<85-90celsius)

well when engine is coldstarted it would run rough and revs jump for a millisecond each 5th second, like a kick or like its pouring gunpowder(well)
into the engine each 5th second so it just jumps.
at idle at half load at no load

while driving, it judders when low load or no load
at sertain circumstances when factors like which gear, how much throttle and
how the road is uphill or downhill,

its always jumping rev each 5second, but when it judders it just judders until
throttle position or load is changed

but at full load its no problems.

and that dissapears as soon it gets warm , about 85celsius, if restart still smooth.

if cold and i check tdi graph then the jumps dissapears while checking.

if warm and running good but full heat on and stand at idle so the engine temp goes to 60celsius (cold) it still runs very good until restart (like just turn off turn on in a sec) and it starts misfiring and jumping

if started hot, no problems, ONLY after cold start.

starts always easy. glowig light works good.

been driving like this for 6 months now its making me insane each morning.

must be an electrical issue.. what do i check?!
vcds gives no fault codes at all.

i have vcds fully activated and can read blocks.

sorry for bad english, long time no write, can read and understand perfectly.
taking all tips, tricks, wonders, questions, answers very happily

i can video shoot the behavior cold/hot and put on youtube if wanted.