In reply to Chris mo:
Ive got a PD130 Ibiza I had the same and it started juddering too over about 80mph, I changed the injector wiring loom and it sorted it, think it was about £50 from VW, easy enough to fit, just remove rocker cover unplug connections from injectors and slide out and fit new. Search the VAG forums loads of info and pics of how to change.
Rob