Nissan Cube Z11 - A/F Alpha B1 Reading at 90-100%: What Does This Mean for Engine Health?

What is the expected A/F Alpha value for a healthy Nissan Cube Z11 engine? The vehicle was initially brought in with a no-start condition. A visual inspection of the spark plugs revealed severe fuel flooding, indicating unburned fuel accumulation. The spark plugs were extremely dirty, consistent with poor combustion. After replacing all spark plugs, the engine started and ran smoothly. However, live data monitoring showed both A/F Alpha B1 values consistently between 90% and 10-than 100%. This reading suggests a lean or rich air-fuel mixture, but the exact interpretation for this Nissan Cube Z11 model is unclear. Is an A/F Alpha value of 90-100% within normal operating range? What could be causing such readings despite proper spark plug replacement?