2006 Ford Mustang will not idle after battery disconnect PLEASE HELP!

I recently disconnected the battery the other day and ever since I can’t get the car to idle right. I’ve tried doing idle relearn and that doesn’t work. Before I disconnected the car it idled great. I also put a set of small cams in it and didn’t get the car tuned but it still idled great. It’s been he’ll ever since I disconnected the battery. Any suggestions please?