Not all cars have a vacuum in the crankcase at idle (or at other engine speeds). My 535i has vacuum while my Scion tC (toyota 2.4L engine) actually blows air out of the filler opening. I've checked this on the same engine in my dad's Camry, and it does the same thing. No change in engine operation either. I wouldn't be alarmed if I were you. The fact that the car is using more fuel could be due to winter fuel and cold weather. Just my $.02