Driving almost like a non kompressor, power lag on take off/around corners/changing down, sometimes not powerful enough to overtake quickly/ safely previous computer test showed purge valve/grounding problem.
Finding a bad ground is tough. If the car has ever been wrecked and painted before a common problem is the ground being mounted back without removing paint to have it go to ground.
I did not have a ground chart for a C200. I am providing you with a ground chart for a C240, which should be about the same.
If you need any further help. Let me know and I will resond ASAP.