Symptoms of a Bad or Failing Air Fuel Ratio Sensor

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Cost of Replacing a Bad or Failing Air Fuel Ratio Sensor

If you notice a decrease in fuel efficiency or engine power output, as well as a rough idle, you may have to replace any air-fuel ratio sensors. Our certified technicians can come to you and diagnose the problem. You will receive a $30 credit towards any follow-up repairs that result from the diagnostic. Following are example prices for Oxygen Sensor Replacement. Click on the button below to get an upfront quote for your car.

Cars Estimate Parts Cost Labor Cost Savings Average Dealer Price
2008 GMC Yukon $364 $294.46 $70.00 9% $401.96
2011 Ford Crown Victoria $213 $142.84 $70.00 14% $250.34
2005 Jeep Wrangler $167 $97.24 $70.00 18% $204.74
2014 Mercedes-Benz CLA250 $263 $192.68 $70.00 12% $300.18
2012 BMW 328i $548 $379.55 $168.00 14% $637.55
2010 Jaguar XF $674 $533.56 $140.00 10% $748.56
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How to Diagnose a Bad or Failing Air Fuel Ratio Sensor?

failing air fuel ratio sensor

An air-fuel ratio sensor is one of the key components found on many modern engine management systems. Most vehicles will have more than one air-fuel ratio sensor. They are mounted in the exhaust system before and after the catalytic converter. The air-fuel ratio sensors continuously monitor the air-fuel ratio of the vehicle’s exhaust and send a precise signal to the engine computer so that it can make real time adjustments to fuel and timing for maximum efficiency and power.

As the air-fuel ratio sensors plays a direct role in the adjustment and tuning of the engine, they are very important to the overall operation and efficiency of the engine and should be inspected if problems arise. Usually, when they begin to have problems, the vehicle will display a few symptoms that can alert the driver that an air-fuel ratio sensor may require attention.

1. Decrease in fuel efficiency

One of the first symptoms of a problem with an air-fuel ratio sensor is a decrease in fuel efficiency. The air-fuel ratio sensor monitors the oxygen content in the exhaust stream and sends data to the computer so that it can add or subtract fuel. If there is any problem with the sensor, it can send a bad or false signal to the computer which can throw off its calculations and cause it to waste fuel excessively. Miles per gallon (MPG) will usually drop over a period of time, until it remains consistently lower than before.

2. Drop in engine power output

Another symptom of a possible problem with an air-fuel ratio sensor is a decrease in engine performance and power output. If an air-fuel ratio sensor has become “lazy,” over time it will send a delayed signal to the computer, which will result in an overall delayed response for the entire engine. The vehicle may experience a sluggish or delayed response when accelerating, as well as a noticeable loss in power and acceleration speed.

3. Rough idle

Another symptom of a bad air-fuel ratio sensor is a rough idle. Because air-fuel mixtures at low engine speeds must be very finely tuned, the air-fuel ratio sensor signal is very important to the idle quality of the engine. A bad or failing oxygen sensor can send an incorrect signal to the computer which can throw off the idle, causing it to drop below the correct level or fluctuate. In severe cases, the idle quality may be impacted to the point where the vehicle may even experience stalling.

Because the air-fuel ratio plays such a vital role in the engine computer’s calculations, it is very important to the overall performance of the vehicle. If you suspect that you may be having a problem with one or more of your air-fuel ratio sensors, have a professional technician, such as one from YourMechanic, diagnose the vehicle and replace any air fuel-ratio sensors if necessary.

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Kenneth

17 years of experience
374 reviews
Kenneth
17 years of experience
Awesome first experience using Your Mechanic. Will definitely use again. Kenneth was excellent and very helpful.
2001 MAZDA TRIBUTE - OXYGEN SENSOR REPLACEMENT (FRONT/UPPER/UPSTREAM, REAR/LOWER/DOWNSTREAM) - COMPTON, CALIFORNIA

Patrick

30 years of experience
865 reviews
Patrick
30 years of experience
2005 HONDA ACCORD - OXYGEN SENSOR REPLACEMENT (REAR/LOWER/DOWNSTREAM) - AUSTIN, TEXAS

Russell

24 years of experience
168 reviews
Russell
24 years of experience
Very quick and hassle free service. Made extra sure that everything was working right before he left.
1996 HONDA CIVIC - OXYGEN SENSOR REPLACEMENT (FRONT/UPPER/UPSTREAM) - EMERYVILLE, CALIFORNIA

Julio

24 years of experience
67 reviews
Julio
24 years of experience
Julio was professional, fast, and efficient. It was nice to be able to have my car worked on while I could be in the comfort of my own home. I would strongly recommend using YourMechanic.
2000 HONDA CIVIC - OXYGEN SENSOR REPLACEMENT (FRONT/UPPER/UPSTREAM) - KISSIMMEE, FLORIDA

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