Iv got the same problem mate. I have a year 2000 V5, was driving along today and all of a sudden the car stopped accelerating properly, i pulled over and it was juddering like mad.(car wont rev over 4000rpm) Can't even reach 40mph. replaced the sparks and it made no difference, tomorrow i will replace the HT leads, I'm praying its not the coil pack as they don't come cheap.