Engine Surge to go with check engine light

My wife noticed and later demonstrated a new "idling" problem in our 2000 1.8T. We had a check engine light for a while, then it went away, and then it came back (emissions workshop). ROUGHLY the same time it returned, we started hearing the motor rev lightly, every second or so, between the moment you put it in Drive or Reverse and the moment you apply acceleration.

So, technically, this is not happening at standing idle. But it only occurs before you take off.

Recent work: Replaced plugs, fuel filter, air filter, interior body panel near fuel fill (recall), gasket replacement to fix "major" oil leakage (on warranty).

I sumbit to your collective wisdom.

Does your car have the braided fabric or rubber vacuum lines. The ones just above & behind the valve cover. The braided ones were bad to deteriorate.

Check the thread I posted earlier today regarding a tip for 1.8T Passats. It is also a vacume line item, and you could be a candidate.

Good luck!