Used my VCDS to diagnose a stumble/die at idle problem that's cropped up in the last couple of days.
Any time the RPM would drop to ~900, it would immediately just die.
Turning it off and cranking, then doing it again would get it started, but the first attempt after it died would only crank, not even attempt to fire up.
It appears that the MAF readings had drifted far enough, and were not responding to the changing air flow, and then causing it to stop erratically.
This morning I pulled the MAF and rinsed it out with some MAF cleaner a few times, and had the VCDS MAF readings go from the prior readings that offset ~200 mg/str at idle from the predicted number, and not responding to throttle movements; now it is tracking the commanded/computed value within 5mg/str and responding quickly to throttle movements.
It didn't give me any grief in the morning commute, so here's hoping it stays in good form, at least long enough to get a replacement MAF on hand.