Hi John, A car knock sensor is located on the intake manifold, cylinder, or engine block, it detects preignition and detonation, potentially damaging forms of abnormal combustion. Though full-blown knocking and pinging are audible to the human ear, the knock sensor detects imperceptible levels. A bad knock sensor may also not let the engine accelerate properly while driving on the highway, and cause the vehicle to lose fuel mileage.

The knock sensor picks up vibration and sound coming from the engine block, turns it into an electronic signal and sends that signal to the engine control unit (ECU). The car’s computer then judges the information and determines whether or not ignition timing should be altered.

Hi Scott, I'm pleased to assist you. The knock sensors are located on the engine block. The 2006 Lexus GS300 Base 6 Cyl 3.0L is equipped with two knock sensors. This is a common configuration for a V6 engine, where each bank of the engine has its knock sensor. Let me provide you with two links below for the set of 2 and 4 sensors (for reserve) so you can choose which one you'd prefer to order while supplies last. I hope this helps and enjoy shopping! Set of 2 - https://www.carparts.com/details/Lexus/GS300/Replacement/Knock_Sensor/2006/Base/6_Cyl_3-dot-0L/SET-REPM311201-2.html?can=CPGG4850_CSQA_20240122 Set of 4 - https://www.carparts.com/knock-sensor/replacement/set-repm311201-4?can=CPGG4850_CSQA_20240122