I have a 2001 KA Luxury which had a dreaded misfire.
Changed plugs and leads - no joy.
Bought a coil pack. On fitting I noticed that there was water on the coil pak; I traced this back to a leak on the NS washer jet; when using the screen washer,water would drip down directly onto the coilpack and it as enough to get an acr and cause a misfire; when it dried it was OK but then it would come back and that was the problem. Changed theoil pak as a precaution as it had been shorting out for a while. Hope this might help someone. Peter