C200 W204, Stutter at WOT and limp mode or turn off
 

I have had a W204 C200 for about one year now. It was acquired used, 2011 car. Drove well the first two months then developed a fault with the DSC Control Unit. Got that fixed. A few weeks later it began loosing power when suddenly throttled hard. Revs to about 3000 then some stutter and a clunky sound from the engine. With this sudden WOT, the acceleration towards 3000rpm is sluggish, as if the car is in Limp mode. Lots of noise, zero torque. If I keep my foot floored it slowly looses power and rpm and eventually dies. OK on restart. It seems to be ok with gentle throttle. It has become dangerous to overtake with it in this condition. I am not too tech savvy with Mercedes but my thought itinerary is as follows,

1. Check MAF, disconnect and test. Clean nonetheless
2. Check throttle body for dirt and vacuum leaks and clean nonetheless
3. Remove fuel filter and check for dirt or blockages, replace if necessary
3. Check throttle position sensor (Would be useful to know how I can test this, it may be sending bogus information when actuated very fast, my thoughts)

I believe it should be one of the above. Any suggestions or similar experiences will really help me decide the best cause of action in attempting resolution. Car is at about 72,000km