The Gates emission control hose for 2003–2004 Mercury Grand Marquis with the 4.6L V8 connects the PCV valve to the intake, restoring the crankcase ventilation route. Use this replacement when the factory hose is cracked or leaking to reestablish proper emissions routing and prevent vacuum leaks that could affect idle, emissions, and engine breathing.

Gates 03-04 Mercury Grand Marquis V-8 4.6L PCV Valve To Intake Emission Control Hose