flow waterjet height sensor.

trying to see if anyone has had this problem,
so when I start to run my program and my height sensor goes and touches of to my lead in it will DO that but when it gets ready to cut it just pauses, jerks for a second then it will not do nothing it will not try to cut .
But if I disable my height sensor and lower it down manually to about .200 above my part, then if I tell it to cut from a point it will cut.
so I am thinking my height sensor is not working .

does any one know how i can go about fixing my height sensor.

thank you