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My 04 Rubicon has developed a sulfer smell. I did some searching and found many people say the cats or O2 sensors being bad. So I figured I would check the easiest first. I have pulled 3 of the 4 sensors and tested them with a multimeter and torch. The highest I can get any of them is .050 milivolts. Not volts, milivolts. Is it possible for all of my sensors to be bad and not throw a check engine light? the jeep runs fine. Seems to have plenty of power. Just has the dang smell when accelerating. It only has 87k miles on it. I just find it hard to believe all the sensors are bad without a noticeable drivability issue. I can imagine I'm doing the test wrong. Kinda simple. Add heat remove it. Any advice before I go replace these.
 

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Usually the sulfur smell is from the cats overheating. But at 87k miles, Its hard to believe they are stopped up already. Mine has 140k and I could still see through them, but I punched them out anyway ;) I hate to see ya replace all the sensors. But as you also pointed out, no cel, so I really doubt the sensors are bad
 

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In my experience the O2 sensors cause low(er) MPG long before they throw a CEL. I replaced them in both if the Jeeps I've owned and I never had a CEL in either one. Not saying that's causing the odor, just relating my experience with o2 sensors.

If you end up replacing them, the best price I found for NTK brand was at rockauto.com, with a 5% discount code you can find online. I wouldn't recommend getting other brands.
 

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Hopefully the torch was not lit. If it was it's not surprising that you saw near 0V, and it's not a good idea! O2 sensors degrade at 1500F very quickly. A torch is around 3500F. You need to shoot unburnt propane at the tip to see if it changes. Even a bic lighter will work. I have a method for customers to test their wideband sensors here.
If the wideband is removed from the car, you can shoot butane from an unlit bic lighter right at the tip and it should go straight to 10:1 or rich. When you remove the butane it should linger and slowly climb back to air. Try it again, but this time blow hard at the tip to remove the butane and it should quickly return to 20:1 or air. Don't burn yourself on the wideband, THEY GET HOT!!
That method is very crude for non wideband sensors, compared to using something like the ELM and torque app to graph out the o2 voltage swings. You can see if they are getting old because they don't oscillate in a normal sinusoidal pattern, or don't oscillate at all.
I had to replace my cats at 7x,xxx mi because they were failing the cat efficiency test. Dealer did it free because I was under 80K!
 
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