Step Daughter problems (need advise)

It's way past time for tough love. When you keep GIVING her stuff that makes you what is known as an "enabler". One car, maybe. The second should have never happened. It's time for a serious counselor, and some tough talk---and be ready to back it up--from you.

One thing that is REQUIRED is rent money, chores around the house, and money (to you) for food.

Add to this the removal of her bedroom door unless her rent is paid and up to date. Been here done this. Make it suck to stay there, and she will leave real quick. I actually bought a cheap fridge; then bolted a pad lock to it, and put a lock on the front door that was dead bolted before I went to sleep. My wife was not happy, but it was either that or a divorce