Did both places tell you that you had a bad battery? Also, Advance is correct in telling you that the alt is regulated through the PCM. However, that doesn't mean the PCM is bad.
What I suggest is to drive the car on short trips. Eventually the problem will show-up again. At that time, take it to a dealer to have it checked. They will be more specific about the problem.
Or, you could remove the starter and have it bench tested. That way we'll know how the alt is working independent of the car's PCM.
Let me know if you have any other questions.
Tuesday, November 4th, 2008 AT 12:50 PM