2001 Impala with electrical mystery

I have a 2001 impala with 8000 miles on it. It has a problem of draining the battery every time the car isn't started for 4 days. Its been at the dealer on and off for 2 months now. After 4 or 5 visits it was thought that the radio/CD player was the culprit. It was removed and the car was returned to me while the radio was ordered. During this time the battery never went dead. Put the new radio in and bang back to the old problem. After another round of dealship visits the black module ( CPU brain) was replaced. Still the problem persisits. I'm hoping that maybe someone has had an experience and solution to help.

maybe the factory amp is staying on too long...or not cutting out..just a good guess

Thanks I appreciate the input. Its been frustrating because any fix takes 4 days to prove. I thought that out of all the threads there might have been another car with the same problem

Tank55, buddy dont feel lonely i have had the same problem. I also own a 2001 impala, but i have replaced the cd player with a pioneer premier and i still have the same problem. You may have thought this or not but i believe the problem lies in the battery. the stock battery only has 600 cold cranking amps, and the problem seemed to me that it only happened when it was very cold outside. I havent replaced my battery yet but i will post you and let you know how it goes.