What is the deal with knock sensors on my 2000 chevy silverado 1500?

[dilpickle513]

about two months ago i had to replace my knock sensors and everything was fine. i had a mechanic do it for me so i know he did everything right (hopefully). Well, now my truck is being sluggish again and sure enough, the guys at autozone told me it was my knock sensors. Why does this keep occuring and what can i do about it.

 

[Bubba B]

Either the knock sensor is bad or a bad connection to the knock sensor.