Over ten years before I discovered the Crossfire I learned something. Changing plugs on a car over 100,000 miles and NOT changing the plug wires as well is a waste of time.
I won't bore you with the story, change those wires today.

The misfires AND the rich condition can be due to bad wires. Seems like a waste of time to try to diagnose such issues with old plug wires, change the wires and go from there.