For the time being this will be my last message on this thread as I will be away from home for work for several days and I won't be travelling with the 245.

The multimeter used was a true-RMS DMM (Agilent U1232A). I don't know if that changes how it reads pulsed DC compared to a "normal" DMM when in DCV mode, though.
A shorter duty cycle would result in a lower reading of the DC voltage, right?

Measured w.r.t. ground, the scope showed a decrease in duty cycle when the load increased.
The way I see it is that a lower duty cycle causes less force to work against the spring tension inside the IAC leading to a larger airgap.

One thing I've noticed is that the high idle state isn't always an arbitrary thing. Manoeuvring the car (in 1st or reverse), touching only the clutch, and when cold has a clearly higher likelihood of making the car go into high idle mode (i.e. 200 rpm extra) than when I do use the throttle too. This does not always correct itself when warm.


Idle


Close to stalling while letting the clutch out slowly with the other foot firmly on the brake pedal.