Vehicle hunts dramatically at idle. Sounds like the throttling is out of control and the ECM is stopping it running away by cutting the fuelling.
No codes in memory although the driver info display shows "engine in failsafe mode"or similar.
Having trouble getting live data for APP and TPS values (will make more heroic attempts tomorrow).
Sounds like a leaking PCV letting in unmetered air but don't know if this engine suffers from this problem like others in the BMW range.
Strangely there is a significant airflow through the MAF which is a constant draft (MAF live data records 1.5V constant and 2.3-2.4V varying slightly as engine hunts when measured by meter at the MAF)and "shading" the MAF by hand has a significant effect on the idle characteristics. If covered by more than about a third the engine stops which would suggest to me the ECM is following the MAF output.
The vehicle has recently had a new MAF fitted (by someone else) which appears genuine and the vehicle has run ok for about 4 months since then.
I intend to check the drive signals to the throttle body but it seems strange there are no codes at all.
Not familiar with this engine and I'm concerned I'm missing something obvious.
Shaun