02 2.7L auto. 2 month ago the battery drained overnight. Battery tested and replaced. Now it happened again, the battery drained overnight. Nothing was left on. Key out. I thought voltage regular but then it should happen every night. Is there a common problem to check first. I am going to hook up a amp meter to the battery and see if I am getting a draw. But it has only happened twice now so I don't think I will get anywhere. Has anyone had a intermittent battery drain?