Wiring harness holding clip broke causing the harness to shift and rub against the frame. Eventually, the vibration wore the insulation on the wires away (within the harness) making them come in contact with one another. This created a short in the electrical system causing No. 6 coil and fuel injector to go out. Labor cost was very high as mechanic had to hunt and peck for hours to find the short in the system. Nuts, a plastic wiring harness clip costing cents on the dollar ends up costing me over 1K in electrical system wiring repairs.