I looked through your search, and found some similar issues with M119 engines but nothing in particualr was the same.

I have a surging idle. In the morning when the car starts up( it starts perfectly everytime) it idles around ~1000 RPMS then after that the idle is normal till the engine begins to warm up.

In park the idle begins surging randomly, as if i was putting my foot down on the pedal to the beat of music. it surges between 700 and 1300 RPMS.

When I drop the car into D The surge goes away, its there but its almost undetectable. until after a while at random, i would say 3 or more minutes at idle it hiccupps. It dosent stall, it surges quickly then it idles normal for a while before doing it again.

When driving the car up shifts are great, almost undetectable and smooth, when i hammer down the gas it takes off like a shot, no hesitation just hard power. Then when i let off the gas, the car stays at RPMS and slowly drops in RPM in sport mode. (I understand this is for cornering to make up for the fact that i cant select what gear i want to be in when i accelerate out of a corner, thus it keeps the RPMS nice and high. IS THIS NORMAL OPERATION for the 722.6 5 speed autos?)

Here is another curiosity. If i drive around 40 kmh the car seems confused as to what gear it needs to be in. It seems like its constanly shifting but, possibly its cutting out. If i tap the gas it instantly responds but when i take my foot off its like i put the brakes on. Before it started doing this i would take my foot off the gas and the car would slowly wind down. Now when I let off the gas it abruptly slows down. Its like the gas is on or off, no inbetween at that slow of speed.

Another curiosity is hills. When i come down a steep hill the car seems like its searching for the right gear. as i come down keeping a constant speed it will seem like it shifts up, then when i start gaining speed it seems to shift down then ill brake a little and it will shift back up then i start gaining speed it shifts back up.

NOW. The transmission was just REBUILT for rough downshifts. When the car went into my tech it idled great and didn't have these problems.
When i got it back i was excited because the rough shifting was gone, but then as i kept driving i started making these observations.

So now to my question. Is there something that he would have touched or removed that would do this? I believe he didn't do the procedure properly. I took it back to him, told him i wasnt satisfied and he told me it is COMPLETELY unrelated to the problem. The car was FINE when i dropped it off now it drives like crap. He says he will investigate the spark and the ignition system. (At my cost) He says he is 100% sure that it was not caused by him. He thinks that its fuel or spark related or perhaps a sensor. i think he screwed up, but i really dont want to spend another 400EUR at some other place to tell me something i already know.

Has anyone had this problem? Or have any techs ran into this problem on M119 cars with 722.6 Transmissions? My AMG has ran flawlessly for a year. and before it went to him it still ran flawlessly it just shifted down to 1st really rough.

I know I know, check the plugs, spark, wires, SIMPLE STUFF Thing is... I don't want to start just throwing parts at it. I need some basis to get going from. Primarily what he could have messed up in there. It ran fine 7 days ago now it runs like a bag of ass.

I Appreciate you taking the time to read this.

ANDY

PS: I am located in Germany, I am American military.