Disconnected wire on knock sensor.

[Fryedaddy]

Anybody have an idea of what this wire is? Is it supposed to be plugged up?

[Ωhm]

Should be shielded wire for the Knock Sensor (KS) signal. Can't tell from photo, but do two (2) wires go to the connector? Note tin foil type stuff wrap around wires, that 3rd wire should connect that shield to ground. Purpose is to prevent electromotive force (EMF) from outside sources riding on the KS signal wire causing a false reading. If you can read continuity to ground on that wire your good to go.

[cruiser54]

And be aware of the routing.