[AngMarius]

Hello, I'm having a strange problem with my engine, so let's start with the beginning
I got this car 1 year ago and I had rebuild the engine entirely, at a bmw dealership changing almost everything ( I'm coming back to almost everything later)

For now the engine is running pretty okay, just some rough idle at cold start and sometimes fluctuate in idle ( from 700rpm to 720 rpm)
So what I did
Changed all orings, changed valve cover, distribution and both vanos, all hydraulic lifters, oil selenoid changed and vanos selenoids cleaned, boost selenoid changed, throttle body changed, pistons changed and weight adjusted so they are all equal, valvetronic tested, compression tested, smoke test for air leak, lambda changed, both water pumps changed, both map sensors changed, maf sensor changed too, blow-off valve changed, and soo on.
Also spark plugs and coils have been changed
All changes with bmw OEM parts directly from bmw.
Pretty much I have 3-4 parts that I didn't changed just checked
-Valvetronic motor seems to be working fine before the error
non return valve for vanos selenoids I didn't checked
tank fuel ventilation was checked and didn't seem to have any problem
temperature sensor looks ok but I'm planning to change it as I already brought it
ecu is the original one as it seems to work fine
Problem is this
Every day when I start the car from cold at around 100 Celsius I get valvetronic 133710 error saying that valvetronic eccentric shaft lower position reached.
Monitoring everything in the car with bimmer link I have seen that whenever I get the error valvetronic will go to 173-175 grades and park itself for error so it'll not touch the valves, and intake pressure drops from 0.950 bar to 0.450bars and even lower, from my understanding intake pressure should be the same as boost pressure meaning 1 bar approximately, throttle body remaining in the same position as with the Valvetronic running so air is not obstructed.
If I delete the error, turn off the car and back on the error will not appear till the next day and everything will work fine, but if I don't delete it pressure in intake will stay at 0.450 bars and valvetronic won't work, also the error is intermittent, sometimes I'll go a week without it sometimes appear every other day

I have no leaks, I'm checked all the cables and everything is perfect, even checked the current for every part.

Can you telle what to suspect next?

Also I've checked all my eccentric shafts and they are perfect and even tested valvetronic with valve cover off and everything is perfect there too no signs of eccentric shaft wear.
Also do I need to adjust valvetronic motor after taking it out?
I didn't do that as I did it with ista to relearn all positions

[AngMarius]

Correct me if I'm wrong, I did all my research without prior experience in bmw engines and using only n13 technical manual

[Devik]

check out my video about the solution:

updated news, totally no code shows now, solution is to clean carbon, walnut blast, n carbon cleaner bottle x6 pour into gas tank, freeway x6, after that on and off code, then just ignore it, few months later, check back, no code on, for months already, so fixed. just to clean the intake and carbon then okay.