clock does not keep time on 2001 Lexus RX300

I keep setting the correct time on the dash clock but every morning when I get in and start it up it is off by several hours. No pattern noticed as far as what it changes to. Any ideas why?

Asked by for the 2001 Lexus RX300
Does the stereo also loose its preset stations? If so check the fuses the same fuse supplies power to stereo radio presets and time clock.
1 more answer
I had the same issue with my Clock (2001 RX300). I brought it to the dealer, they wanted to change-out the entire radio at my expense. I decided to pass on the costly repair. A few weeks later, the car battery died. I tried to jump the battery but it wouldn't take a charge. I put a new battery in my RX and WAALLAAAA, clock started working again. I think a dying battery was the cause.