So i recently bought an audi a4 and the same day i got it the engine light came on, i had it scanned etc, called the dealer i bought it from and they told me to bring it back in the coming wednesday, I did an oil change on it last night and today i took it around the block for about 15 mins and lets say i was hitting around 130/140km, after that i took it off, took about an hour nap then went to buy something to eat and the engine light is now gone!, but the engine sounds like its idling a bit more rough now, was just wondering if there was actually a problem that needs fixing or if the problem was self fix or if there is a possiblity of it returning.

Im new here sorry if im in the wrong section, do be gentle