Strange Appearance Today

Hi together, today something strange happened to me: I drove the car about 50 m out of the parking garage this afternoon and left it outside for about 4 hours. When I threw it at him afterwards, he ran like on three pötten, not unround but very rough and shaky. BurnouTT then (thanks again) via CarPC and VAG-COM read out my error memory (funny car session with USB cable from one car to the other). Except an error message in the engine STG about something with “Power Source Connection” (English VAG-COM) or so similar was only a message to find that the onboard voltage was too low. Is my battery soon after about 20 months soon weed? Also a STG reset did not bring anything. Climate was also not on. Then just let the engine run, until the increased stationary gas flattened due to cold engine and see there: with continuous warming the shaking became less and less, until then it was completely gone and I warmed the car times a round During the ride there was nothing more to feel about it. For this the car wg. of the reset and the 8 °C went off like devils (scratched once in the second gear at 2,300 rpm 1 bar charging pressure) Strange is that he had this “3-Pötte-Erscheinung” quite exactly a year ago, when I wanted to go to Kaunitz to the VW/AUDI-Meeting, and then never again. Is my car a bitch or what is going on???? Let’s see how it runs tomorrow morning.