2001 toyota idling at stop every 4 to 5 weeks on 2001 Toyota Camry

approx every 4 week the car will idle at a stop. it starts to shake a little at the wheel, then alternator, check enegine and batties lights come on it shuts off. I then put it in park. turn it off start it up and then it runs like a dream until next time

Asked by for the 2001 Toyota Camry
It sounds like your idle control valve is wearing out or is getting dirty. This is the area that I would inspect.
Thanks..Is the idle control valve replacement an expensive job.