What's That Sensor For?

[rogi]

On my 2001 Explorer XLT SOHC 4L, there is a sensor underneath the air intake, all the way in back where you couldn't possibly reach it without removing said intake. I had to remove the thermostat housing (upper and lower) before I could see it, and I'm concerned because the shroud on the wire running to this sensor has melted in a couple places near the Therm Housing.
Does anyone know what this sensor is for in case I need to test or replace it or its' wire assembly?
Thanks,
Rogi

 

[snoranger]

Knock sensor.

 

[2000StreetRod]

knock sensor

The knock sensor similar to the one installed on my 2000 is shown below. It's mounted low in the valley between the heads.

Do the photos look like what you're referring to?