94E420,
I am having a similar problem although mine actually stalls.I believe it is related to the Air Mass FLow but have a few more tests to run. Off course mine is on a different engine style and older and simpler 560 so they may be completely different.
m

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Martin Ingram
Colorado Springs
2005 320 CDI
2006.5 VW Jetta TDI
1991 560SEL (179000 Sold)
1972 280SEL 4.5 ('The Lead Sled' 320000 miles when sold.)
1972 220D (225000 when sold)