Coolant Temperature Sensor bad. Which one should I replace?

[EagleTalonTim]

I just finished putting an O2 sensor on the car because I was getting really bad gas mileage, but I was also told that because the car does not idle higher in the morning that it could be the Coolant Temp Sensor too. I don't know which one to replace.

There is one that has one male connector. I know that controls the gauge.
The one right next to that has 2 male connectors. Not sure what it is called so I cannot replace it.
The other one is towards the top of the thermostat housing facing towards the intake. Not sure what that is either.

Which one do I replace to get the car to idle higher in the mornings so it will quit stalling on me?

 

[4G63_Attack]

the one on top of the thermostat is the fan control sensor.
the plug with one wire is temp meter. right next to it is the temp sensor for the ecu (with 2 wires).

 

[EagleTalonTim]

What is that called? Orielly's cannot find it in their system. They have the gauge sensor, and the fan sensor but don't list anything else.

 

[4G63_Attack]

you have to go to the dealer for that sensor

 

[bling5tatus]

Pepboys had the sensor there next time I checked... it's the one with 2 male connectors that are perpindicular to eachother... on the lower side of the water neck closest to the head.