CTS and temp gauge

[EJL1985]

It's been awhile since I have last posted, however I could use some help. I've searched and read the old topics on coolant temp sensor and water temp gauge and they were helpful, but heres whats going on with my s13 with redtop.
Problem 1:
My idle is inconsistent. It almost cuts out (sometimes does), catches, then revs back up before dropping back down... ect. I removed the connection from the ECU temp sensor and the motor idles perfect. Should I replace the sensor?
Problem 2:
Water temp gauge in cluster. I checked and cleaned the connection on the water temp gauge sensor (one wire). The gauge is stuck on full cold. If I manually lift the needle to HOT then let it drop it tries to catch half way, but settles between cold and half way. Then I turn the car off and the needle drops to full cold. It seems like it is getting signal but is too weak to lift the needle.
What's going on here!!!?

[Blown240sx]

Replace the two wire sensor with a new one of the same motor year, so if its a notch top S14 then it will need a notch top s14 2 wire sensor, s13/s13, and so on. The single wire temp gauge isnt as important but if you want to replace it just make sure its the same as the model 240 it is in. So if its in a S13 then put an S13 sensor in it.

[EJL1985]

Then that is what I'm replacing next! Thanks