hi, i have a r reg vw golf gti 2.0 16v, it faild the mot on emmisions, but cant solve the problem it judders at 3000rpm and stops at 4000rpm. i have checked the cat and lamba they are ok? i got a friend to put it on his computer and it comes up with ecu blocked????? surley if the ecu is not workin the car would not run but it does the only problem i got is the juddering???? can u help its doing my head in