The general consensus seems to be that code is usually tied to a vacuum leak somewhere in the system, as you seem to have surmised already. When I've run into that, my troubleshooting consisted of examining all of the vacuum hoses for disconnected or cracked lines, along with any of the bellows and hoses that connect the MAF to the intake manifold. Don't forget the brake booster that runs on vacuum either.
The professionals use a smoke machine that is hooked up to the MAF and blows smoke into the engine. Any leaks quickly become obvious when the black smoke comes out the place that's causing the problem.
You might try some of the VW forums like [link|https://www.vwvortex.com/|VW Vortex] and search up vacuum leaks to find out where people are finding them and how they fix them.