Son is home for winter break so he has been using the Forester. Last night he got home and told us the battery is dying because he forgot and left the lights on while chatting with his buddies at the mall parking lot. Charged it overnight so I could started it and took it to Costco to get a new battery.
After switching out the battery, the car would started and with the engine ran for a few seconds, then died. Tried turning it several times and same result.
Son googled and found out there was this idle relearning thing. So after disconnecting the old battery, leave the car off for 30 minutes. Afterward put the key in and turn to ignition without starting for 15 seconds. Next start the car and let it run for 15 minutes. Turn it off and wait 5 minutes, then start the car and run it for another 5 mins.
Yes, the wife was totally not please since she had accompanied us to Costco, less then a week after her stomach surgery to remove a tumor. However it really worked.