I'm searching mercedes forums non-stop looking for info but I figure I'll throw this out at you guys.

I bought the car used 3 months ago at 26K miles. Its always had this problem for me.

When accelerating anything more than light acceleration, at around 1800-1900 rpms, about 20 mph, the car loses acceleration. Power just goes away. Then a second later it kicks back in and everything works fine. The problem is very consistent, whether the car is cold or warm or the acceleration is medium or hard. It seems only very light accel avoids it.

A mercedes forum had a guy with the same issue, no one could resolve his problem, but they mentioned something about variable cam timing and how the second cam kicks in around that point, and to make a long story short it made no sense but I figured I'd toss it in here for you guys.

The problem does not seem fuel related since the car runs fine and accelerates fine, its just this blip at this one exact point. Its not a sputter either, its a full 1 second cutout.

Just FYI, I've replaced fuel pump, spark plugs, intercooler pump, oil change, tranny fluid/filter change since I've had the car. I have a needswings intake but thats only for the past 2 weeks. Also, the car pops and shakes a little at idle but that problem seems unrelated, and much more frequent in the MB forums. I'm investigating that too.

I have an IAT sensor and camshaft position sensor ready to be installed that I randomly bought for fun.... I just haven't had the time. (Camshaft sensor, not to be confused with crankshaft sensor)

I have a spark testing light ordered that apparently I can point at a spark plug wire while the car is running and it will tell if the wire is working. Never used one before, should be interesting...

The chances of this small community helping me with this strange problem is pretty slim compared to the larger mercedes community but I wanted to post it up anyways just in case someone knows or if someone has a similar problem.