08 Subaru Legacy-rough idle unless AC is ON

[K-Rad82]

Purchased 2008 Subaru Legacy for my son. Super nice condition, drove great during test drive. thought this would be a great first car. 118k miles. Drove an hour home, that drive was fine. Started up 3 days later and took for a short drive and ended up stalling out. There was oil places there shouldn't be. Dealer replaced Engine valve cover and spark plugs. Drove much butter but we thought it was still a little off. Cleaned Mass air flow with cleaner. Drove around a bit and then all was good for a few weeks. Until....I took the battery out to fix the airbag light issue that a lot of Subaru's have. Airbag issue is fixed but once I Put battery back in it now idles rough and wants to die. Did Subaru idle re-learn fix video I found online. Now drives fine IF you have the air conditioner ON. If AC is off, it still sputters when you are in D or R and come to a complete stop. My next idea is to clean the throttle body but after that I don't know what to do. Any ideas? I appreciate your thoughts. Trying to avoid a big mechanic bill. Seems it is just something little. No check engine lights or anything. Automatic transmission