Hello Gentleman. I just dropped my 3.0 into my 2005 Ford Ranger and everything came out according to plan. However, under the passenger side, there is a mystery part, which I believe to be a sensor, but I do not remember where it goes. The attached picture explains better what I am looking at. Specifically, where does this circular-looking part that is surrounded by black plastic goes bolt

to? Thank you in advance for your time and consideration.

 

Looks like a Knock Sensor, bolts to the side of the block usually near motor mount on the passenger side

Not used in every year on 3.0l Rangers

Looks like 2005 3.0l did have KS(knock sensor), and green and yellow wires match as well

 

Yep, you are right Mr. Ron. Looked it up and that is what other sources say. Thank you for helping with this as these types of parts were not part of what I grew up working with which were mostly older vehicles.

 

Knock sensors are fairly new, needed electronic spark systems to use them, or manually controlled spark like on the Model T's, lol, "ears" were the Knock Sensors

Pinging or knocking is a common issue when using 87 octane fuels(regular gas), and it will damage engines
'When Knocking is detected spark timing can be advanced slightly to prevent it, there is a loss of power but no engine damage, so its a trade off