Eddy:
Look at the top of your screen and you'll see a DIY tab. Someone did a pretty nice writeup, with photos, of the wiring harness replacement for the E320. I did this to my car last year; the job was not difficult at all and all of the previous engine-related problems immediately went away with the new part installed. I hope your issues will be resolved as well! Do a search and grab some popcorn, cuz you'll be reading for a while.
Brian

__________________
Brian
1995 E320 wagon