How do i tell my dad i want to live with my mom?!?!?!?!?

Wow that's tough! I would say try and talk to your dad but I don't think he would listen. Its sad to think he would let your stepmom treat you and your sister differently form her son. Maybe your mom could help, ask her to get things going by talking to your dad first and breaking the ice so to speak. Depending on your age and the state you live in, YOU can decide for yourself who you want to live with and theres really nothing your dad could do about it, you would have to go to court first though. I would talk to your mom first, like I said maybe she can get some dialogue going witrh your dad, good luck