The Toyota dealer told me it was the knock sensor?

The knock sensor is very delicate if you over tighten it it will break, here is the location of the sensor and how to replace it also they had problem with the wiring connector so you might want to ge a new one.

The Knock Sensor is located on the right side of the engine block above the starter.

Toyota does not specify a torque value for the knock sensor. So just snug will work.

Check out the diagrams (Below). Please let us know what happens.