Not all polluion control devices are bad, or rob your engine of power. The PCV, or Posive Crankcase Ventilation is one of them.
The PCV valve fist started appearing in the early '60's to remove
oil vapors fom the crankcase. Prior to the PCV,
oil vapors were vented by a road draft tube which puffed the
oil vapors into the air, and onto the road.
The valve operates on a spring which opens the valve only under vacuum, idling or cruise. When you open the throttle, vacuum is decreased and the valve closes under sping pressure. The PCV goes in one valve cover, and the breather (or connection to the air cleaner) in the opposite valve cover. You can put you hand over the beather opening and feel the vacuum. Without the PCV, you'd get oil all over your engine. The PCV, if kept clean with a little Gumout periodically, will last forever, and keep you engine innards clean. If it gets clogged, the extra air from the PCV is absent and the engine runs rich.