Ok so a couple weeks ago I didnt realize my 4runner was running without coolant so it overheated. I had someone bring me antifreeze. when i got home it started leaking from the valve cover gasket. so i replaced it. 2 days later I the check engine light came on and i got a code 52 which is the knock sensor. I didnt hear a knock and my vehicle was lacking power so i new it was a bad sensor. when i took off the intake the plug between the harness and the sensor was shaved so i replaced that as well. when i put everything back it was running fine quick response no lack of power but i still had the code 52 even after i reset it. now i dont know what it could be i dont hear a knock so i dont think its anything major. if you can help that would be awesome.