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1997 Ford Taurus P0133: Oxygen Sensor Slow Response, Bank 1 Lean/Rich Codes Explained

Model: 1997 Ford Taurus Fault Code: P0133 Posted: 2008-01-26 17:52

Hello everyone, Here are the key details of my vehicle: - Year: 1997 - Make: Ford - Model: Taurus - Engine Size: 3.0L (VIN "U") - Mileage: 107,000 miles - Transmission: Automatic My check engine light recently came on, and I've been retrieving three diagnostic trouble codes: - P0133: Oxygen Sensor Circuit Slow Response - P1131: Bank 1 running lean - P1132: Bank 1 running rich Given that the vehicle is showing both lean and rich conditions on the same bank, I suspect a failing oxygen sensor. I've been told that O2 sensors typically degrade around 100,000 miles—so this may be a case of age-related failure. I’ve already inspected all wiring harnesses and vacuum hoses; everything appears intact and properly connected. The sensor is located before the catalytic converter, but I'm unsure which side of the engine it's on. Based on standard configurations, I believe Bank 1 refers to the side where cylinder #1 is mounted. If you're standing on the passenger side and looking at the front of the car (facing the belt/pulley assembly), the right side is likely Bank 1. My main questions are: 1. Could this issue be caused by something other than a faulty oxygen sensor? 2. What exactly is the location of Bank 1 on the engine? Any insights or advice would be greatly appreciated—thank you in advance!

Related fault codes
P0133
Comments (2)
Anonymous 2008-01-27 10:33

It's highly likely that the issue stems from a failing oxygen sensor. In most vehicles, Bank 1 refers to the side of the engine where cylinder #1 is located. If you don't have access to a service manual, contacting your local dealership can help confirm this layout. Good luck—please update us on your progress after any repairs or diagnostics.

Anonymous 2008-01-28 21:11

Thanks for the clarification! I was concerned that cylinder #1 and Bank 1 would be on the same side, which makes sense given my vehicle's layout. I was hoping it might be the front-facing sensor since it’s exposed and easier to access. I don’t have time to work on this until the weekend. As a precaution, I’ve cleared the codes and drove the car to work today—so far, the check engine light hasn't come back on. I’ll monitor it closely in the coming days.