I'd bet either your overboost is kicking in OR you have an intermittent leak in your vac system which is keeping the p2 flap from closing....

PS- I am closer to you now, in ecobb just over the river. I will work for beer.

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1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42