PCV should be in the top of the intake manifold, next to the valve cover. There should be a rubber hose that runs from it to the valve cover. Or it is located in the valve cover, if you have a 16V engine.
O2 sensor is in the exhaust manifold. Has 1 wire coming from it, going to the wiring harness (or 3, or 4 wires, if you are talking about a later model trackick).