52 code on 1995 toy forerunner

I have the same after replacing the engine I have tried a new sensor new wiring new computer x 2 still have the same problem, I ran a different wire from the knock sensor now mounted with a nut welded the the engine lift point in through the cabin which was a coax cable shielded Earth still have the same problem lots of people have this problem has anyone ever fixed it? I had the computer sent away and tested OK as well ,still code 52 only

ok I fixed it today after using two new knock sensors which did not work!! I replaced it with a second hand factory knock sensor and finally it worked! so the aftermarket knock sensors are not good enough! I used fuelmiser brand, so don't rule out the knock sensor just because its new if nothing else is working and you know the wiring is right, hope this helps someone as most posts you never hear the end results