either a bad piston ring or you have a massive leak somewhere.check if you have blue smoke coming out of your tailpipe.bad piston ring would mean you'd need to rebuild your engine head, which means you'd probably want to rebuild the entire engine since most of internals are disassembled.i've known lot of people who just live with oil burns though. (as long as you keep adding oil) think about how much the car is worth and how long you're goin to keep it and see if it can justify couple thousand dollars of repair cost.