Check engine light keeps coming on after repair

What is your question?

check engine light on indicated faulty 02 sensor. sensor was replaced but check engine light came on again this time indicating vacuum leak. vacuum leak repaired (replaced air intake hose) Check engine light is back on indicating 02 sensor again. Can a vacuum leaks foul out a brand new 02 sensor? what would be the next step? Should the vacuum leak been repaired first before 02 installation? Roger Warren Baltimore MD roadmaster99@netzero.net