Hi, I recently bought a second hand K7 and had same sort of issues, call it miss fire, cough what ever, but after looking at many threads from many places thought it could be fueling as it only did it when warm and running low revs, so decided to bite the bullet and buy a Dynojet PCFC which came loaded with appropriate maps for Vee's from 2002 - 10 the K7 was setting No 2 which leaves loads of spare setting positions to load free maps from Dynojet onto the PCFC and at a twist of a pot can change it instantly, you can also tweek different other settings in the map range to experiment yourself but I have just set mine onto No2 and the missfire has gone, money well spent, did not need the V5 one the PCFC was adequate.
Paul