93 cutlass supreme where's knock sensor?

I have a trouble code that says to check the knock sensor, I've got the Haynes manual but it tells how to change it but not where to find it. The guy from the auto parts store said to look on the firewall side of the engine block but I don't see anything, it's a3.1L.

talked to autozone just now 36.99 for the part and it is located passenger side under intake manifold inside the block hope that helps