Q: Misfire rough idle

Changing the radiator should not have caused a misfire. Replacing the plugs and the MAP sensor was a great idea. What we commonly refer to as the O2 sensor is not located in the fuse box. There are two O2 sensors, and both of them are on your exhaust pipe. One is located between the engine and the catalytic converter. The other is located after the catalytic converter. These would make your engine idle roughly and not perform as desired. My thoughts are that you may have had more than one issue going on at the same time. With the age of your vehicle, its time for things to start showing some wear and tear. You should check your fuel filter and make sure it has flow. If it doesn’t allow gas to flow through it, your engine will be depleted of what it needs. Make sure your air filter is clean as well. If you would like, a certified technician from YourMechanic can come to your home or place of business to diagnose the rough idling.