I have had the same problem for a couple of years on a clk 230. It's had a new maf and lambda sensor and air recirculation unit/flap. None of them have fixed the problem.
I take it into mercedes, they hook it up to star and clear the faults, they then spin it round the block without using the kickdown, and then return it to me and charge me £90.
I then drive home and use the kickdown on the motorway and the problem comes back. Thats happened twice now and I can't afford to keep going back so they can take £100 from me.
I try keep it under 4K Revs and then it doesn't go into 'limp mode'. If you do kick down or floor it the revs shoot all the way to the end and the car goes nowhere fast.
I personally think it want's a new auto box but they were not listening and said they don't just put in a new auto box for no reason and instead go off the faults.
The other faults if they can compare in anyway to yours are that the car must warm up for a good five minitues before setting off (otherwise the gears will not change).
The new replacement maf I got was the proper Mercedes Bosche one too and not an ebay replacement for £30. The other parts were genuine too apart from the lambda which was from eurocarparts.
