181K miles on the original wire harness must be some kinda record. I replaced the harness on my '95 E320 about 4 years ago when it had 64K miles on it. I had all sorts of idle and perforance problems that only got worse as I changed plugs, cleaned the MAF etc. I opened the old harnes and the wire insulation was a dry powder. I consider myself lucky that a short circuit didn't damage any electronics or start a fire.