I 've kept her running for 27 years but may have hit the end of the line. Any help is appreciated since my trusty mechanic has retired on me and I am faced with a car that I don't trust any longer.

My issues are that the engine starts but runs rough and very rich for about 5 minutes. After that it smoothes out but still runs rich. I recently replaced the air mass meter because of a problem with the car cutting out at random times. Before the AMM was replaced, the car was checked to see what happened if the AMM was unhooked and it would always start again, so we replaced it with one from a junkyard. Prior to all of this I had changed the plug wires and plugs. Thinking that the plug wires would seat on the plugs without the plug tip screwed on, since that is what the package said to do, I placed them on that way. After about a year the car wouldn't pass smog (California car) and the mechanic noticed the plugs had been arcing inside the wire insulators. I put the plug wires on correctly without replacing them with new ones and the car ran fine for two years. About three months ago I finally replaced the original O2 sensor.(309k miles by that point)

After testing the coil with a multi meter, the results indicate that it is out of spec. and the AMM indicates that it is slightly out of spec.

Where am I going with all of this? Could I have triggered my current problems by running the car with the arcing plugs and then not replacing the wires after seeing what happened, possibly damaging the coil? Is the issue with the AMM a random event that just compounds the problem?
If I replace the coil, plugs and wires, and the worn distributor cap rotor along with the AMM, will I know happiness and reliability once again? Is there something else I should be looking at to solve the rich running condition.