Misfiring, stumbling at cold starts, lean mixture codes?

2010 BMW 535I
110,000 MILES • 3.0L • 6 CYL • TURBO • 4WD • AUTOMATIC
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RENALDO27
  • MEMBER
  • 1 POST
My BMW is rough idling on cold starts. Stumbling down the road, idle surges up and down really rough.
Got 2d2e codes and mixture codes for both banks
Mostly bank 2 is very lean.
Idle surges really bad at cold.
Did the fuel injector test. Replaced two of them.
I also changed the MAP sensors, new throttle body, new MAP sensor, new lpfp.
Hpfp not done.
Rest of the fuel injectors didn’t seem bad.
I replaced all 6 coils and spark plugs.
And done the valve cover itself along with new PCV vent hose.
I’m running around circles here with what’s going on.
I tried smoking the intake with no results. I’m fed up at this point.
Feb 20, 2024 at 8:14 PM
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JACOBANDNICKOLAS
  • ✓ASE Certified Mechanic
  • 110,194 POSTS
  • ASE Certified Mechanic
Hi,

By chance, do you have a live data scan tool? If you do, could you let me know what the short-term fuel trims are with the engine running, at operating temperature, and at idle? Also, check the coolant temperature sensor signal before starting it. See if it is close to the ambient temperature.

Let me know.

Joe
Feb 21, 2024 at 7:27 PM
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