Find Subaru Impreza Oxygen Sensor Replacement Cost. Shop Subaru Impreza O2 Sensor Spacer & Subaru Impreza Sensor Cleaner. Explore Subaru Impreza O2 Sensors. Maintaining the oxygen (O2) sensors in your Subaru Impreza is crucial for optimal performance and fuel efficiency. To ensure longevity, avoid using leaded fuels and ensure timely servicing of your vehicle's engine management systems. If you notice a decline in fuel economy, rough engine idle, or if the check engine light illuminates, it could signal that your O2 sensors require replacement. Choose the right sensor by matching it to your model year and engine type; options include titania and zirconia sensors, each with distinct response times and longevity. High-quality materials and precise installation are paramount for these sensors to accurately monitor exhaust gases, making them pivotal in managing your Impreza's emissions and overall health.