Here is an update about the car that may help others.
I checked if I can get access to the CPS sensor from above the vehicle. I was not able to access it from above. I checked below the vehicle and it looks like I would need to remove the starter and some elements of cruise control (there is another post with pictures detailing the removal).
The main two causes from various postings were CPS and MAF sensor. I decided to have a shop (not a dealer) that specialized in German cars run diagnostics on it since I did not want to replace the MAF sensor without knowing for sure it is the cause of the problems (and the CPS is such a pain to replace).
The failed part was the MAF sensor. They will replace it for the charge of the diagnostics ($80). The MAF sensor was $290 (remanufactured Bosch) which is about the same I would pay at autohausaz web site. I hope the above info helps someone else.