Beacause of the cold crappy weather it seams to get to the GTI it needs a warm blanket
dont know if this will help but thought id offer as i problem solved it myself and found out what was wrong.
I had similar problems and also starting was a nightmare making me late for work eveymorning everyone that walked past me had a good stare, leaving from light or junctions was also a nightmare juddery spluttering then when it got around 2000rpm shed pull away ok!
I spent a couple of hours on it and a few quid to sort it, if these things i said are happening to your GTI i would do the following.
This is what i did
I ended up cleaning the throttle body and the breather pipe DEFO RECOMMENDED THESE GET CLOGGED UP WITH CRAP!!!
Then i changed the fuel pump relay, ecu relay and temp sensor listening to the others on line, i would do this last if i was to fix it again because it did not make any difference and i would of been £30+ better off as all the old relays and sensor are fine, now its running i checked them but couldnt take the new ones back as they had been fitted.
I then checked my plugs which were ok, then dizzy which was ok, to remove this use a screwdriver to undo the 2 clips either side. To replace it put it in its nearest position and spin it left and right and it will slot in and wont spin no more then just push the 2 clips back on.
If you have like a dark layer on the gold contacts in the cap i would give it a little scrape with a little flat screwdriver or something similar and it will ping off, then empty any dust in the cap, check the rotor tip which is the T shaped thing thats still connected to the engine, this also has a gold tip check for dirt and clean.
If it still persists change the coil which i did then my GTI was running a dream
