Your gasoline engine goes through some exhausting work.  Yes, it's truly exhausting, as in: it produces exhaust! And when your engine starts behaving like it's exhausted, such as running poorly or getting lousy fuel economy, the trouble may be something called a PCV valve. Did you know it's a series of explosions that creates the power in your engine? The spark plugs ignite a mixture of gasoline and air and BANG! A whole bunch of those and you're engine is humming away. Leftover vapors from those explosions go into your crankcase, which is also a place where engine oil goes.  Those vapors still have a lot of unburned fuel in them, and if they had nowhere to go, they'd turn your oil into a thick mess called sludge, not good for a smooth running engine.  Engineers came up with an idea. Re-direct those gasses building up in the crankcase into the engine's air intake and mix them with fresh air.  That way the unburned fuel could go through the engine again and produce p ... read more