The knock sensor on my 97 SE checks out 588 kohms when the car is cold. However, when the engine is hot the reading now indicates an open circuit. (I also have a permanent 0304 trouble code)

Is is safe to say the sensor (or perhaps connector) is shot ?

 

If you have the 0304 all the time, yes, it's dead.

Check eBay, they can be had for less than $100 shipped.

(Mine was $83)