On a 1986 Mercury Cougar with a 5.0L FI engine, the PCV valve is typically located on the
passenger side valve cover. It's usually a small, round valve with a hose attached to it. However, the exact location can vary slightly depending on specific engine configurations.
To be certain, consult a repair manual specific to your 1986 Mercury Cougar 5.0L FI. A diagram will show its precise location. You can often find these manuals online (some are free, others paid) or at auto parts stores.
