It's not the spring, starting to see this on all golf 7 just needs slight modification to flap as it jams along side where the plunger sits on body
George, Have you seen any fixes for poor mpg, frequent DPF regens or slightly down on power for the GTDs yet? My Scirocco 170TDI was quicker (noticeably most in 5th and 6th gear acceleration) and 10% more frugal than my GTD, and I never had a single active regen in the whole time I had it.
My MK5 170TDI PD had similar issues which were fixed with a service remap.