Oxygen Sensor

chevy-guy · February 18, 2005

Will a bad oxygen sensor make me have bad gas mileage?

Shaners · February 18, 2005

Most definatly!!! Also cold temps and "Winter Blend" fuel will hurt your MPG's too...

boomer 33 · February 18, 2005

Will a bad oxygen sensor make me have bad gas mileage?

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A bad 02 sensor can casue all kinds of driveability problems, if you suspect it is bad I would check it out

97whitez71 · February 18, 2005

I don't mean to hi-jack the post, but will a bad O2 always set the service engine light.

boomer 33 · February 18, 2005

I don't know if it ALWAYS will, it should, and it should also store the trouble code in the computer.

hercman · February 18, 2005

An aging O2 will not set a light as long as the PCM is adjusting to keep the sensor readings happy. That's why MPG and engine performance is reduced. Once the PCM reaches the limit it can adjust now your sensor will trip a light. Replacing the O2 sensors when you change plugs and wires is a good idea.

Bish · February 19, 2005

An aging O2 will not set a light as long as the PCM is adjusting to keep the sensor readings happy. That's why MPG and engine performance is reduced. Once the PCM reaches the limit it can adjust now your sensor will trip a light. Replacing the O2 sensors when you change plugs and wires is a good idea.

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Agreed. Mine started to get real lazy around 90K. I could actually watch the response time with my obd software. IF it fails, it will set a code but if they are progressively getting slower to respond it won't be till the end that they trigger a light. My mpg went up 2 after progressively getting worse up until I replaced them.