Skip the auto shop - Our mechanics make house calls

Q: O2 sensor causing misfire.

asked by on

I have a misfire. The computer is giving me a code that says the O2 sensor is at fault.

Hello. If you have a misfire, most of the time that will set a misfire code. If the only code that comes up is an O2 sensor code then you may have a bad oxygen sensor or you might have a fuel mixture problem. The most common cause of a misfire that I have seen on this engine is a bad valve seat. Most of the time this will set a misfire code for that particular cylinder, but not always. What a mechanic would do to diagnose this would be to install a computer scan tool to see what the O2 sensors are reading. If the voltage of the sensor is not fluctuating then the sensor may be bad. If it is then they would check the fuel trim readings to see if there is a fuel mixture problem. I would enlist the help of a certified mechanic that has a scan tool and knows how to read this data, like one from YourMechanic.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Car does not move in forward gear, previously had a burning smell in car

From what you are explaining and from my experience with this vehicle it does sound like a transmission failure. It is common for the forward clutch back to fail all of a sudden, or for the forward clutch case to...

Q: Gear shift stuck in park.

The most common cause is the gear shift selector mechanism plastic lock release in the center console falls apart. The fix is to replace the shift control mechanism under the center console. There may be some aftermarket repair parts available,...

Q: 2000 Toyota 4runner-both oxygen sensor replacement

If you input your year, make and model, as well as location (zip code) at YourMechanic's oxygen sensor replacement service page, the exact written quote you desire will be provided. Generally, after about 100,000 miles of use, it's not a...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.