Buck,

Do a search for "surging" you will find lots of information. I had that problem and it ended up being a clogged intake with stuck flaps. Its pretty easy to take apart. Are you getting the Check Electronics Message?? I had the surging without it for awhile when it got bad enough then the message came up. Where are you located?

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Dennis
2006 E320 CDI Black/Black Leather. Nav, HTD Seats HK stereo 32000 miles.
2000 VW Passat 1.8t 300,000 miles as of Dec 09, 2009 original owner
1997 E300d Silver 300,000 miles As of Jan 05, 2010
3rd owner SOLD