Knock sensor again

1991, 3VZ-E - Problem returned. After changing the knock sensor wire averything was just fine - for two days. Now check engine flashes again showing knock sensor code - what could it be this time?
Please help ASAP!!!

bad engine?

What do you mean?

the sensor is picking up a sound in the engine that it thinks at there is a knocking noise so it makes the timing of your engine fall back as to not damage it Maybe your engine is really knocking?

The engine is after complete rebuild, there's no knock in it, it's working with no vibration (almost).

The ECM wouldn't give an error code for a sensor picking up an incorrect signal. The sensor doesn't know it's doing the wrong thing. It's in the sensor or the wiring or the ECM. Is it possible you damaged the wiring installing the intake manifold or something you needed to remove to access the knock sensor the first time?

To get to the knock sensor almost everything must be removed. There's hell lot of work to get to it, but i did. Brian R. - you gave link to page that said that it's almost imposibile to have knock sensor damaged. So I changend the signal wire (knock sensor itself is rather expensive). Everything was just fine - it had power like never, and than BOOM - check engine lamp again - checking for the ECU codes and I can't believe it - showing 52 - means knock sensor.
Yesterday I decided that either I can fix it or I sell my 4R!
Near the air intake there is that connector of this f***n sensor. I used a spray that cleans electronical connections.
Guess what - it works - well for now. We'll see for how long.
Best regards,
Thanks for help.

You're welcome - Good luck, I think you've found the weak point.