To locate it definitively:
1. Consult your owner's manual: This is the best resource, as it will show a diagram of your specific engine.
2. Look at a repair manual or online diagrams: Many online resources (like Haynes or Chilton manuals, sometimes available for free online in PDF form) have diagrams showing the location of the PCV valve. Search for "1991 Chrysler LeBaron [engine size] PCV valve location."
3. Visual inspection: With the engine cold, carefully inspect the valve cover. Look for a small valve with a hose connected, often near the back or side. The hose usually connects to the intake manifold.
Remember to be careful when working around hot engine parts. Let the engine cool completely before attempting any maintenance.