UPDATE!
I plugged in my tuning software, and found one code: 1095, which is “mass air flow ahead of throttle vale implausible (too high)”. Now, the car does have an IPD plenum and 997 GT3 throttle body, but it’s running a tune to adjust airflow and has been doing so for several years with no issue.
On visual inspection, I did find that one of the hoses running from the the AOS to the TB was maybe a little loose, and also had some oily residue around it. Pulling that hose, it looks like there is a little bit of oil in the hose. I disconnected the hose from the AOS itself, and there was more oil at that end. See attached pics.*
So: follow-up questions: 1) might this loose hose (if it was indeed loose) have caused that idle surge and error code? And 2) is the oily residue a warning sign that my AOS is beginning to fail?
