The K2 series was a MK3 model seen here:
Hmmm your rough idle could be a few things:
- Injectors are clogged; suggest getting some injector dump in cleaner
- Check your plugs and wires if they look fouled or damaged it's worth the replacement
- You could pick up a VAG-COM kit to help diagnose the problem as seen here http://www.onboarddiagnostics.co.uk/vagcompart2.htm
or here http://www.ross-tech.com/
Best of luck!