best would be to descend to FL100 and go to nearest airport under a Mayday call(smell fuel?= fuel leak?), open ram air, get lot of fresh air, close all packs and if necessary, slow down to less 200kt, and open a window.
when it doesn't do what you want it to do, get to basics and fly the plane. Get this plane manually and go for visual landing. Jump on the break, and get out of the plane.