What could it be if the last two weeks you have started smelling a weird greasy odor that smells like an auto repair shop?

Your ventilation system may be taking in "fresh" air from under the hood, and something under the hood is fouling the air. It may be a PCV hose that is not connected, thereby letting blowby gas to be spewed into the under-hood air. It could also be oil or power steering fluid dripping on something hot, such as an exhaust manifold or exhaust pipe.