Hi, I have a 1989 irocz 5.7L with the 350. I've been having the dreaded idle surge and complete loss of throttle response while driving. I was pulling the plugs to check them today and noticed this sensor in the picture was disconnected. Upon further inspection, the male end that actually plugs into this sensor was broken. If looking at the engine from the front, this sensor is on the left side of the motor between cylinders 3 and 6 I believe. I appreciate any help identifying this!

 

Knock Sensor

 

Fan switch... The picture is shooting up showing the starter solenoid, fusable links, dipstick. Since this is the passenger side, it is a fan switch.
If this were the driver's side head, it would be the temp sender (for the gauge).

Knock sensor is down at the oil pan rail, and has a large donut of a metal housing.

 

 

Yep, that's it. Thanks!