I have 96 4x4 I6 sport. Yesterday i left my lights on at work. I had it jumped off and driving home it would miss fire. Drove it later that night same thing. Then today I came out the battery was dead. Put it on a charger then tried the starter just ticked. then I had it jumped again and it started right up. So I had my battery tested It checked out same with the alternator and got a new starter a while back. Oh and there was acid bubble on the positive terminal post.
My question is what could be causing the battery to drain?

 

Bad battery. Bad alternator or a bad ground. Clean your battery cables since you said you had some crud on them.

 

"My question is what could be causing the battery to drain?"
*Leaving your lights on all day can do that.
*If it's an old battery, running it down like that can finish 'em off.. I'd charge it overnight and wire brush the posts and terminals. If it won't hold a charge, replace it.