98 2.7 high idle, surging when clutch pushed in

So the last couple days have been really cold here, temps in the negative teens-
I noticed yesterday morning after driving my truck it idling around 2k when stopped and the idle surges if im at speed and push in the clutch.
Im hoping its my thermostat stuck open a hair causing it, the heater works great still (very hot) so I have my doubts. According to my scan tool temp is staying constant around 187 degrees.
I cant find anywhere what normal operating temp is on a 3rz equipped tacoma or what degree thermostat they come with stock. Any suggestions?

 

Finally threw a code for o2 sensor bank one, replaced it and no more issues.