Where is the knock sensor on a 2001 impala?

The knock sensor on a 2001 Impala is located on the left (driver's side) of the engine block, just below the cylinder head and towards the front of the engine. It is bolted to the engine block with a single bolt and has a single electrical connector plugged into it. The knock sensor is a small, cylindrical device with a black plastic body and a metal diaphragm on one end.