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Discussion Starter · #1 · (Edited)
So I took my 2010 750li (N63 4.4L F02 body) into dealer to perform the Valve stem replacement due to high oil consumption. After I got my car back CEL came on. running rough at low RPM (500 or so). Runs fine when driving.
Took it back to dealer, they deny they have anything to do with it.
I went home and plugged in OBD and shows mixture lean, 101F01 and 118001, 118401. So I pulled up the sensors, MAF seem to be fine, since 2 banks value are really close. The problematic value is the intake pipe vacuum after throttle.
I am getting 600 hPa for bank 1 and 411 hPa for bank 2. ( That means bank 1 is loosing vacuum? Because it can't draw it as low).

I just did a smoke test, (took out air box, hook my DIY smoke into the air intake to turbo). and I get smoke coming out of the front of the engine. youtube link:

I have not figure out where exactly the smoke is coming from. But I assume its' not normal to see smoke at all?
N63 smoke test leaking in the front

It's getting dark now. So I'll try to pin point the location tomorrow.

Update: I checked again and smoke is coming out of intake manifold ( the one connects to throttle)... Does valve stem replacement touch that area??
 

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740i 2015, 535iX 2011
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I'm not expert in N63 but you can check TIS, for replacing all valve stem seals.

I checked but didn't go deep, some intake connections required to be removed but not sure about your leak.
 
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