So I have been fighting this Corolla low idle at the stop sign thing for several months now. I just happened, by chance, to turn on the headlights as it was looking like a bad storm was coming and I noticed that the low idle thing was gone all day. So if I turn the headlights off and the daytime running lights are on the low idle problem is back. Turn on the headlights and it is gone. Weird. Car will idle at 800 RPM steady as the first day I bought it. Turn off the headlights and the darn thing almost stalls at a stop sign. Everything turned off in the car except the headlights and all is fine. Everything turned on inside the car and the headlights on everything is fine. Turn off headlights and low idle problem is back again. I have decided to just manually turn on headlights and drive it.