I have exactly the same problem but what did you do to take care of your problem? I noticed a problem when we were on our trip to California my wife said it started to happen about 6 months ago but the problem went away and then it came back again. So I took my car to a dealer in California but they said they had to order a new cd player and it would cost me $950, I didn't know if labor included or not and it would take one week to arrive.
The bad thing is my warranty 4y/50000miles, and my car is 4y3m eventhough is only 36000miles, it won't qualify for the warranty.