Changing the Coolant Temp Sensor (help)

[mechanism]

Hey everyone, I have a 1999 Falcon AU and I was just wondering how to change the coolant temperature sensor.

Can anyone tell me how hard it is? I have had a look and it looks pretty tight around the back of the engine near the firewall. Do i need to remove anything to get at it?

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Here is the problem I have been having and why I have decided to replace the sensor
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Driving on the freeway or revving much up around the 2000rpm causes my temp gauge to fly up above the 'normal' position (between the n and the o on the dash), this also causes the engine to go into a low and rough rpm (probably controlled by the computer to protect it from overheating). If i stop and let it idle, it cools down quite quickly and returns to the normal point. so i have to drive like a grandma and avoid freeways.

First I thought it might be the cooling system itself so i flushed it and changed the thermostat and the upper radiator hose (just cos i had a new one).

still the same problem.

Then I thought it was either the thermo fans, or the water pump. But on second thought, it wouldnt cool down quickly at idle if it were. (right?)

So i read a thread on here where someone describes almost exactly the same problem and it turned out to be the coolant temp sensor. So thats what I am going to try to replace.

any thoughts, tips or ideas as to the easiest way to do this or if you think it might be a different problem?

note: i'm not loosing coolant so its not that.