Check engine light

i have a 1997 ford tbird and it failed inspection for the check engine light was put on code reader came up with the code for an 02 sensor replaced the 02 sensor and the light came back on again, can you maybe give me some idea as to what the problem or problems be

Does the same code still come up?

have not put it back on code reader as of yet

The condition and tune of the engine greatly affects the oxygen sensors. Have a mechanic bring the engine to a good tune.