So this occassional issue I have with an idle that is too high (happened twice this week) started after I filled up with super unleaded. Picked up the car from the dealer on the monday (who had put ordinary 95 in it), filled it with the BP 97 stuff on thursday night and had issue for the first time on the Friday...
could just be a coincidence....I might try running on 95 for a tank or two to see if the problem goes away...unfortunately nothing comes up when the dealer attaches vagcom.
Ran my mk 5 GTI on ultimate for the whole 4 years I had it and never had an issue..so I doubt it is the problem