I just replaced my Engine Temp. Sensor that goes under intake
manifold #3, it is a two wire sensor. As opposed to the temp.
sensor between manifold #1 & 2 which is a one wire part.
The two wire sensor plug seems a bit to big for me to be able
to get a socket onto the part to tighten it up without the
feeling that I was going to break the plug on the piece.
I used a crecent from under the manifold, but then I had rewired
my harness and I have more room down there right now.
If the two wire sensor is not working it will cause your engine
to rev. high and low if you can even get the car to start without
the sensor in place. FYI.