You are running lean, first check for vacuum leaks, loose or broken intake any thing that will feed the engine unmetered air. If it is a leak it should not be hard to find. If you have a vagcom go to group 000 then click basic settings and look at block 2 if the number is less than 30 you have a leak.
If you do not find a leak check air filter then your maf and b1s1 o2 sensor output since the feedback from those sensors primarily determine adjustments to the fuel air ratios. The adjustmens in the short term fuel regulation do not usally effect cold start. Beyond that could be clogged injectors, or fuel filter. The fuel rail pressure test will tell you if adequate fuel is being delivered to the injectors.