Where is the knock sensor on a 99 Toyota 4Runner?

The knock sensor on a 1999 Toyota 4Runner is located on the engine block, typically on the driver's side, near the intake manifold. It is usually positioned beneath the intake manifold, making it somewhat difficult to access. To reach it, you might need to remove the intake manifold or other components that obstruct access. The knock sensor is a small cylindrical component that detects engine vibrations to help adjust ignition timing.