Surging Passat

I own a 2001.5 VW Passat wagon that surges slightly forward when the car is idling. I have had a VW dealership look at it and they said it was a vacuum line leak. I had them replace all of the vacuum lines, but it continues to surge while idling. I was in an auto parts store some after the dealership replaced the lines and the guy behind the counter had also owned a Passat previously, and he told me that there was a simple fix to the problem, but I don’t remember what it was. Some kind of a valve or gasket or something. If any one knows about this, please help, I am planning on driving up to Rhode Island from Virginia very soon and I would like this problem resolved if possible.

You MAY have a broken or loose TPS (Throttle Position Sensor).

If so, you’ll get intermittent bursts of fuel from the injectors and an unstable idle because the PCM thinks the throttle is moving.