TB will judder, the potentiometer on mine kept misreading, so it was always aligning, one minute power, next feck all then some camel juddering making me look like a twit that can't drive. I wouldn't rule it out as that does not show up on the dash either. But as said vag-com will straight away pinpoint or show you what the problem is.
Plus varied-warranty cars are renown for having a faulty TB sooner or later
