My mom co-signed for my car. I have made all payments and down payment too. She and I are on bad terms...?

If you were to go to court and provide proof of payments from your finances, then no- You would however have to refinance your car so it would only be in your name. She cannot take the car away from you, she is simply a place for the bank to go if you default on your payments. Not a legal owner. You should look into refinancing it; I am sure there is somewhere who will do it for you-