There is quite a bit of work getting to the knock sensors but its not hard. you just need 2 to 4 hrs on hand to disassemble and reassemble. You have to:
1 - drain the radiator by disconnecting the lower hose.
2 - remove throttle body unit, and hoses
3 - remove intake manifold, and hoses
4 - remove fuel injector rail and injectors
5 - now to the knock sensors, The lower part of the intake where the fuel injectors were installed, has to come off to get to the Knock sensors.
6 - Remove the 10 to 12 screws plus 2 nuts in front and 2 in back that secures that lower intake unit.
7 - lift out the lower intake unit out and you will find the 2 knock sensors 1 screwed to the left side of the engine and 1 to the right. If you didn't drain the antifreeze, it will spill out when you lift the intake out. 22 or 23 mm open end wrench to remove the sensors.

Hope this helps someone!