I have a 1996 Explorer, and changed an oxygen sensor just the other day. All I needed was a 7/8" wrench. Since the year of the vehicle is different, the sensor might be as well. Give it a try!
Yea, its always a 7/8" socket or wrench. It was the same on my Honda.
I have a 1999 escort there are two sensors one before the catalytic converter and one after I just changed the one before. you need a special socket for the oxygen sensor. simply get the socket from any auto parts store like Advance or Autozone. open your hood, looking at the spark plugs the sensor is just below the plugs on the left. unplug the sensor and attach socket(hardest part), unscrew the sensor. Replace with new sensor and connect wiring, Close hood. Finished. . Cant help you with the one after the catalytic convertor because this fixed my problem.
By the way while you are under the hood if your engine is misfiring then check your spark plugs and wires for proper gap it could be that simple and you could actually avoid spending alot of money on what is a simple fix. I recommend you do the spark plug thing before the oxygen sensor.