High/Pulsating Idle at Cold Temps


I have a 2003 Corolla with 97,000 miles. In the past month or so, as its gotten progressively colder, the idle is very high when I first start it up if the temp is below about 45F. In addition, if I just let it sit for about 30 sec. or so, the idle will begin to pulsate or surge, like I’m stepping on the accelerator - but I’m not. This surging will last for a couple of minutes before the idle comes back down. If I begin to drive immediately after starting the engine, then if I come to a stop shortly there after, the idle will then begin to pulsate until I get going again, or if I don’t come to a stop, I can feel a surge coming from the car - sometimes through the accelerator peddle. If seen a couple of entries about a similar issue in a 2004 Corolla and a 1999 Camry, but neither entry wrote back to explain what the problem was and if they got it fixed (and how much it cost). Can anyone suggest what may be causing the issue AND what is done to correct it.