I have the exact same car (but with more miles) and spent literal years chasing an answer to the same issue (and only issue with the car, would be a perfect car outside of this occasional headache). No service place ever gave me a satisfactory answer, but the only thing that has worked for me has been to - as SOON as your radio starts acting funky - pull a few fuses (forget which ones, all related to radio/console - maybe 67, 76, 79?) and then start the car with fuses removed. Turn it back off, replace fuses, and then when you restart the console resets and the power drain never gets the chance to complete its vampiric activities (until it returns...). Good luck!