Vibration from the engine at cold

[Racataian]

Hi,

it happened to me several times that after some days spent at cold, the engine is accelerating very slowly and above 3000rpm the whole engine/chassis is vibrating. This happens only until the engine warms up, then it runs smooth, no increased fuel consumption and no DTC. 

I noticed that I see this effect after 1500rpm, the idle-ing is smooth. I was thinking that maybe an injector is to blame but I checked them a few months back and they were fine. Could the injection pump be to blame?

I need to run a diagnostic with VCDS later today...

[Racataian]

Update: no DTC is shown on VCDS