Of late, my '09 2.0T CC has been experiencing increased rough idle (used to be only occasionally) and a sputtering feel while accelerating or holding steady at rpms up to about 4k. The car still pulls hard and there does not seem to be any loss of power. But that silky smooth feel is lacking. The "sputtering" to which I refer is fairly subtle. Feels kind of like the rough idle, only while actually driving.
Any ideas? Help.