Random stalling at lower speeds - Surging at higher speeds

[andrewwynn]

My first repair six years ago on my e53 was nearly identical symptoms caused by faulty cam sensor.

Crank sensor failing will cause the same. It's lucky if you get an actual code usually you have to sleuth out from symptoms.

I've never seen a case where you get a code for cam/crank sensor and that part isn't worn out.

That part is "mission critical" as in the engine won't even start much less run without it. It's stupid precise as in the computer is estimating how many tenths of a millisecond before three next pulse to determine if the next power stroke delivered. If it's late even a handful of tenths it knows there was a misfire.

Anyhow it needs a new crank sensor get only OEM or you will likely have symptoms with no error code related to the part.