How do you change an oxygen sensor on a 1994 Honda Accord EX?

If the sensor has never been changed it may need to be heated with a torch in order to loosen it up if it will not loosen right away with the socket. Don't use force until it is heated slightly which will contract the metal and make removal easier before stripping or breaking it necessitating drastic measures. On a 1994 Accord it is located on the exhaust system next to the catalytic converter. You unplug it and then loosen it with a socket wrench that has the slit on the side ( an O2 sensor removal tool). You screw the new one in and then plug it in. If the check engine light is on you need to take the car to a mechanic or to the auto parts store so it can be cleared.