Knock sensor??

How would you know if your knock sensor was about to go or gone,whats the symptoms????I have a 01 legacy b4 auto

its hard to tell if its gone some people say the car burns more juice im not sure about that. im 99.99% certain it throws on the engine management light tough when it is gone because the air to fuel ratio would be distorted...basically A knock sensor assures that you're getting as much power and fuel economy as possible from your engine

thanks for the info

Hi will throw up a cel and will see power loss whilst cel on. wat probs are you having?