It only occurs on rapid acceleration -- when I immediately floor the accelerator. If I depress the accelerator gradually, there is a smooth power curve and no lag.

I compare it to turbo lag since it appears the car is waiting for something to "spin up" before it accelerates.

__________________
2008 E350 4matic / Black/Anthracite

------------------------------------
Gone but not Forgotten:
2001 E430 4matic, 206,xxx miles, Black/Charcoal
1995 E320, 252,xxx miles, Black/Grey
1989 260E, 223,00 miles, Black/Black