O2 Sensor

[Pete]

Hey fellas and gellas, Bigpetesmallmeat here with an issue. I have a 2004 F150 with the 5.4L that has a rough idle. I did some scans and I found the O2 sensors were a bit weird. Bank 1 was shifting from 0.04 to 0.80 and bank 2 was stuck at 0.84. My question is, which one is bad? Should they be fluctuating indicating exhaust passing through? Or is the one that doesn’t move not triggering because of being bad or having no exhaust fumes to measure?

Thanks! 🙂

Topic

[Cody]

The voltages for both should be oscillating. I’d swap out the one that’s not changing voltage.

[Pete]

Good enough for me. Would that cause a rough idle? Like, shakey idle. No codes. Got spark and all.

[Cody]

Yeah, for sure. Along with crappy acceleration and bad fuel mileage among other things.

[Mathieu]

The O2 sensor after the catalyst converter will have a high voltage with a high temperature. Higher the exhaust is, higher will have high electricity. You need might need to replace the catalyst converter but you might also check for exhaust gas leak before the catalyst converter top to the manifold just by prevention.

[Author]

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