Where are the oxygen sensors located on a 2001 chevy impala? And how do you change them?

The oxygen sensor should be located on the front engine block on the right of the fan. You will notice one thin white wire going to it. This wire is spliced it to the system. Simply unscrew the unit in the block and pull out of the motor. Cut/disconnect the wire - reconnect the new O2 sensor after you screw it snugly into the block and reconnect the electrical connection.
Where are the oxygen sensors located on a 2001 chevy impala? And how do you change them?
The oxygen sensors are located in the exhaust system behind the engine and in the pipes running to the rear. One will be before the catalayic converter and one after it. The are different, so make sure you replace with the proper one.