I don't know if this will work, but just replace two knock sensors on my car whick had retarded timing and everything whent well. I understand that you replaced yours also. First did you tourqe them properlly? 10 to 12 ft lbs. is all they require with some thread lock. Too tight and they are rendered useless. If so then I would look at the alternator sending a siginal thats causing a bad reading from the knock sensor. You may disconnect the belt from the alternator breifly crank her up and see if this is the cause. If it is two methods of fix 1,reroute the wire away from the alt.2, Sheild the wire on the knock sensor,May sound funny but I read somewhere that covering an object with a zinc coated, say for insenstance small grated wire fenceing will stop unwanted electro waves from contacting the part to be protected. Something smaller than regular chicken wire would do, couldn't hurt to try. Sound crazy
but what ever.
Good luck.