My 92 400E does the same thing. I can back off on the throttle a little and the oscillation will stop. I can then continue to accellerate once I settle it out. Yes, it is near redline, yes the tranny is kicked down...

My shop doesn't see the problem because they refuse to drive the car that hard when testing. I can understand their policy.

I had always thought it might be a fuel delivery problem. That the pump(s) just can't deliver enough.
My 500SL can sometimes do it too... The fuel injection systems on them are completely different...
...and that's the funny thing... they don't always do it...

I do hope that someone on this forum knows exactly what it is.

__________________
02 S500
92 500SL
92 400E (Sold)
87 300E (Sold)
83 300D Turbo (Sold)
75 300D (Sold)
74 240D (Sold after 20 years)