Having a confluence of issues with my Six at the moment and unsure if related. I first encountered problems with the revs plummeting as I came to a stop, with the car struggling to not stall. This developed into occasional stalling when stopped at lights. I now also have the issue that the car is very hard to start - with it cranking for a fair while before catching and immediately dying three or four times before I can get it to run. Unsure if related.

Other than a lumpy idle, the car runs well when going with no hesitation and plenty of power.

My first thought was the CKPS, but the car does show 200rpm while cranking so is that ruled out? I’ve cleaned the TB and IACV with no improvement. Battery is very new and cranks at about 10.75V.

Not sure where to go next…

 

You should check for a vacuum leak somewhere. Could be the intake manifold gasket giving away.

When was the last time you replaced the oxygen sensors?

Is the Coolant Temp Sensor original? Less likely, but a $20 part and 5 minutes of time.