The oxygen sensor installs in the upstream position on 1988-1989 Subaru GL, GL-10, RX and 1990 Subaru Loyale with the 1.8L H4 engine. 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 350-33091 Oxygen Sensor Features:

• Fits 1988-1989 Subaru GL, GL-10, RX; 1990 Subaru Loyale with the 1.8L H4 engine
• Sensor location by application: B1S1 (bank and sensor number)
• 3-wire narrow-band oxygen sensor
• Titania sensing element
• Built-in heater for fast warm-up
• M18x1.5 threaded mounting with a 22 mm hex, 450 mm (17.7 in.) overall length
• Female rectangle connector at the harness end with 3 spade terminals
• Platinum electrode layer with a protective coating against combustion residue