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Symptoms Indicating a Faulty Lambda Sensor

Model: (Various brands) Various
Part: Oxygen sensor

There are clear signs that indicate our lambda sensor is faulty: first of all, the engine warning light is on. The vehicle seems to operate normally, but the light indicates a problem. An increase in fuel consumption with a decrease in mileage per tank; higher fuel consumption without apparent reason; an irregular idle with the engine stuttering when stationary and unstable, fluctuating idle speeds; abnormal emissions with black smoke from the exhaust and a strong smell of unburnt petrol, and of course, a loss of performance, with slow acceleration, especially when the engine is cold. The lambda sensor measures oxygen in the exhaust gases to optimise the air/fuel mixture: if it does not function correctly, the car pollutes more, damages the catalytic converter, and reduces engine efficiency.

Posted on 9 February 2026 by ScegliAuto

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