kyGS400

Took my 1998 GS400 to local mechanic, it would not run normally upon morning start up or at dead stop accelerating. We changed the plugs with Denso, then he checked the O2 SENSOR and checking O2 sensor on DRIVER SIDE
he found that the wires going to the connector the covering of the wires had melted off and touching, don't know how far down it was melted. Can this wiring harness be purchased separate or how can I fix this problem.

Has any one seen this before, if so how did you fix it?

Any record of ever a service bulletin covering this?

Boy I been having problems WITH MY 1998 gs 400 for 2 years. Are there any confident "HONEST" lexus mechanics near Lexington, KY. I will never go back to dealer, I took my car to the dealer in next town over and they just replaced two O2 sensors ( $600 ) and sent me on my way, well in 5 miles the service light back on, I called back and ask did they drive the car, well no the computer told them what the problem was then the service mgr said oh yell you need a fuel pump $600.
EVERY SERVICE I HAD DONE IS ALWAYS $600.