My shielded wire from the O2 sensor to the ECU...that is badly aged and
cracked, resulting in it shorting, again, from the signal wire inside to
the metallic shielding.   It's happened recently and again just yesterday..

.so I am wanting to replace the whole wire, all the way from the O2 sensor
to the ECU..

Second question:  Where might I source wire like that...and no, I don't
want to replace my whole wiring harness...especially since I am running a
hybrid inline power VW motor in my 84 Vanagon...   I was planning on
simply  running another shielded wire across the engine compartment in
parallel to the harness that carries the original wire (somewhere inside
it) and there by solving my cracked and brittle wire shorting out problem...