the previous post is correct, the harnesses degrade badly. any bare wire you see means more you can't see. the throttle body harness has the same wire that's crap, just tougher outer insulation.

give it to a shop and they'll tell you put harnesses on it and then we can see if there's a real problem. stray voltage in harnesses you can't see make for strange issues out of the blue. good luck, chuck.