I purchase my car about two weeks ago. While driving back from school I got a check engine light. My buddy hooked up his scan tool and it read the code 0325 "Knock Sensor 1" and 0330 "Knock Sensor 2" we replace the knock sensors and the knock sensor harness. After about 50 miles the check engine light came on with the same codes. Does anyone know what the problem is and what I need to check. Please Help

99 4runner 3.4 v6
Thank you in advance