Would it be possible to raise my gpa from 2.75 to 3.5 if I'm a jr in high school?

I'm thinking of becoming an automotive engineer and I want to graduate high school with atleast a 3.4 gpa. I'm currently a jr and the school year just started. Right now I'm in all academic classes and I am getting real serious about my grades. If I aim for atleast an 85 (B average) and above in all classes this year and take some pre ap classes senior year and try to get the same grades, would it be possible to achieve my goal?