Ghost Sensor

can anyone tell me where I can find the knock sensor in a S-10 truck 4.3L V-6 This thing as given me a fit and the code says it is bad. Had the engine partially removed yesterday and still could not find it. Looked all around the engine block, specifically on the passenger side between #2 and #3 exhaust and around the oil filter. HELP PLEASE
Thanks

found where the sensor should be, but there is a bolt simply plugging the hole and no wire running down from the distributor. There is chalk marks around the bolt so I am sure someone has worked on it before. Any reason why that is plugged without a sensor and where does the wire come from exactly.
Thanks