ill try switching my MAS relay out with another one from another 190E i have access to and see what happens.

on the other hand, could this be related to why my check engine light doesnt appear when I have the o2 sensor unplugged and leave the car running for a few minutes? on my dads W124, the check engine light came on when I left the O2 sensor unplugged for about 5 minutes, but on my W201 it never came on. i could probably even drive all the way to work with the O2 sensor unplugged and it wouldnt make a difference!