[Jeffro]

One last thing... that GROUND right on top of the intake manifold, toward the driver side of engine has been a source of problems for lotsa folks. (probably not in this case though, since that ECT sensor is referenced to a signal ground at the ECM) But check that it's clean, no corrosion, and all the ground wires going to it are intact. That ground is #39 in the diagram below. #8 is the ECM connector behind the glove box.

 

[Jeffro]

And here is ECM connector B diagram

 

[Jeffro]

Here's a little bit better diagram:

The GRN/BLK is a SIGNAL GROUND from the ECM on pin A23.
RED/WHT is the signal into the ECM.

 

[Jeffro]

Yeah, it was reading 140F once warmed up and idling.

That's pretty low! Thermostat is something like 190°F.

 

[Jeffro]

the idle is a big strange, whenever I turn the steering wheel, the idle speed would shoot up a lot, like over 1k rpm.

The only thing I can think of is the power steering pump load on the engine. When that changes by turning the wheel, the pump puts more load on the engine... but it shouldn't jump up a LOT! Scratchin' me haid...

 

[Jeffro]

still shows up

The wire from the ECT sensor ends up at pin B8 on the ECM

You could possibly check for continuity or a high resistance on the wire.

 

[Jeffro]

Now the coolant temp is reading on my OBD reader and the gauge goes up.

Is it a plausible number?

Check connector for corrosion?