The 4-wire narrow-band oxygen sensor is a replacement sensor for 1999-2002 Mercury Villager and Nissan Quest with the 3.3L V6 engine in the downstream position. It signals whether the exhaust is running rich or lean so the engine computer can trim fuel delivery. A built-in heater brings the element to operating temperature quickly after a cold start.

Walker Products 350-34106 Oxygen Sensor Features:

• Fits 1999-2002 Mercury Villager, Nissan Quest with the 3.3L V6 engine
• 4-wire narrow-band oxygen sensor
• Built-in heater for fast warm-up
• M18x1.5 threaded mounting with a 22 mm hex, 640 mm (25.2 in.) overall length
• Female square connector at the harness end with 4 spade terminals
• Platinum electrode layer with a protective coating against combustion residue