The sensory that detects misfire is the crank position sensor. If a cylinder misses, the math doesn't work out for the expected position of the crank. I think that's where the smooth operation values come from that's just educates guess.

Since you aren't getting codes, you made be in a similar situation to me when I first bought my X5 but in my case was the intake cam position sensor.

No codes never drove funny but would stall with increasing frequency when moving short distances eg pull forward to turn left when the light turns green.

I would get codes but just random cylinder misfire nothing CPS related.

I think you may be experiencing a very similar thing.

Imagine if you will, the cpk is reading but adding or subtracting milliseconds from the timing of the crank. The car will have fits trying to figure out when to send the fuel and spark and will definitely mess with performance.

I forgot if you said you changed cam position sensors. That could also cause performance degradation.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)