......or just a coil pack!!!!
I recently had trouble with my S3 running rough almost misfiring, after vag-com pointing towards maf sensor and knock sensor i decided to start with the first, after replacing the mass air meter with a genuine new one i found no difference.
Back to basics, stripped the engine covers and checked all pipe works for leaks to find nothing.
After getting my mate to look at it with a fresh set of eyes he sugested checking coil packs, un-plugging one by one hey presto un-plugging number 3 made no difference!!!
Lesson of the day.... use vag-com as a direction not a diagnostics.
oh and if anyone needs a MAF sensor i have a cheap one going!!