Hello everyone.

I bought a w164 om642 last year in ianuary. Since then, when warm outside, car keeps surging at low constant speed in the 1000-2000 rpm range. If i press or depress gas pedal, surging stops.

I found out that the EGR keeps cycling about 10-20% continuosly. At idle its fluactuating between 15-30% causing rough idle. If i unplug the EGR, it stops surging but it also stops actuating the turbo vnt, so car drives fine but no boost/no power.
Made bunch of tests with DAS, everything came out good except for egr auto test, wich came with bad results for o2 sensor. Tested o2 sensor with different das procedure, o2 came out good.

Help?

https://youtu.be/ge7Y6aDhLhw

 

My c350 is doing the exact same thing if I boot it there's lumps of power if I'm below 1500 revs it's OK but and kind of slight acceleration feels like small surges of power I've replaced the egr valve non genuine part I've removed inlet manifolds checked flaps I've blasted out the egr cooler I've changed turbo back pressure sensor still not go anywhere with it
if I find a fix I will send a message but upto now it's slightly annoying