Trouble with idle speed

[Ivan141]

I dont know any thermostat that will raise the temps, but you can use pretty much any corolla thermostat for 4A engines, they're all the same.
How far do your temperatures drop? On my car the coolant got cold while driving on the highway, and my heater also had zero effect. That was due to a broken thermostat. But you should notice the meter going down to around 1/4 of the scale and lower if that's the case.