Misfire

B1 S2 is the one for the CAT... suggests its unplugged or something... not having the post CAT sensor plugged in affects fuel trims and adversely affects fuelling... its plausible that this is causing the fuelling to run rich which in turn could lead to misfires...

Fix this issue first and then go from there as either way this needs to be right..

<tuffty/>

Yes a coil would http://www.ross-tech.com/vag-com/m_blocks/010-019.html

The sensor is screwed in to the back of the CAT on the drivers side... there is a plastic cover attached to the floor pan where the sensor is plugged in electrically... I doubt its a fuse as more fault codes would come up for other sensors as the feed gets shared..

Blown coils packs will not show up directly but misfire counts etc would if it was a genuine misfire and not a fuelling hiccup... incorrect fuelling will cause hesitancy that feel like misfires but its not due to a faulty coil pack...

Fix the obvious fault first and go from there...

<tuffty/>

You will either need to replace the sensor with a known working one to eliminate it as faulty... if the known working one still shows the same fault (after clearing the original fault of course) then you will need to trace the wiring back until you find a break or something in the wiring loom

No way to test the coil packs realistically... if they are fairly old its almost worth buying a new set and know they are good... faulty coil packs either just let go completely and the engine sounds like a scooby or they misfire as soon as the boost kicks in as they aren't strong enough to keep the spark going...

I would also check the plugs... mapped engines should be gapped at 0.7mm form the std 0.8mm

Process of elimination and ensuring that all the required serviceable components are at their best...

<tuffty/>