When I start my '03 Corolla its idle speed is around 1200 and later after driving for a few miles it settles down to around 700. Other than that it starts well and runs smoothly. I tried to back off the idle adjustment screw and found out that the screw was barely touching the stop. In older models I used to be able to fix or repair the cold idle in engines with a carburetor, but am totally clueless regarding fuel injectors. This condition also happens when I start the car during the middle of Texas summer (100+ deg).
The car has 123,000 miles. I have not ever changed the plugs, but as i mentioned the engine starts and runs smoothly. As expected, the idle speed responds well whenever the air conditioner is turned on. The engine temperature comes to the mid gauge as always after driving a mile or so. No engine check lights come on. The car always passes the annual smog inspection.
Any guidance here will be greatly appreciated.