For the O2 question, the quick n dirty method is connect your meter on 'duty cycle' setting and see if it reads 50% steadily. This indicates a faulty O2 sensor. For more in-depth testing which might assist you in identifying a marginal O2 sensor or other problems, see this post:
My LAST ovp/eha question, I promise!!!!
For testing plug wire resistors, see this post:
Ignition wires 300E
Resistance for all will be either 1k 2k or 5k ohm If
you can get the resistor out of the connector. If not, you may need a new set.
Next test, wait till after dark. Start the engine, raise the hood and look into the spart plug holes. Do you see any blue sparks?
This will indicate flawed insulation on the plug wires.