# Bad O2 sensor symptoms?



## gogogirl (Mar 13, 2005)

Hi.

My '90 Stanza (auto., KA 24E engine) alternately bogs down, then surges; the catalytic converter overheats when driven just a short distance; and has symptoms of vapor lock (won't start after running until it cools off- about 30-45 mins.). Could a bad oxygen sensor cause all these symptoms? It's been over 30,000 mi. since it's been replaced (I think)...

Also: When I do go to replace it, is there a regular-type metric socket that I can use instead of having to buy an O2 sensor socket?

-Thanks-


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## Asleep (Jan 19, 2003)

are you sure your cat isnt clogged?


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## gfriedman (Oct 12, 2005)

Have you checked for a blocked cat


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## Darktide (Jul 29, 2004)

I agree that it probably is a clogged cat, but just remember that most of the time a faulty catalytic converter has a cause so you may want to check that out too. But don't go by the symptoms now as most of what you're describing is a clogged cat. Good luck and keep us posted


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## Asleep (Jan 19, 2003)

gfriedman said:


> Have you checked for a blocked cat


lol, you must have hit submit right after me...


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## gogogirl (Mar 13, 2005)

*cat. overheats, anyway...*

Yeah, it overheats (or glows red-hot when it's dark enough to see it), but I was told by an experienced muffler man that it could do that w/ out being clogged- That if there was pressure coming out of the tailpipe (whick there is) that it was overheating due to a too rich fuel mixture and that I needed to find the cause of that to fix the problem. I have since replaced the O2 sensor and apparently that wasn't the problem- it's doing tha same damn thing!

(a little history)... A couple of yrs ago, these rip-off "mechanics" replaced my fuel pump and my car has not been the same since. One of the things I found at the time (& haven't checked on since) is that the hose going from the filler (gas) to the tank had a crack at the hose clamp (just outside top of the tank). Could this cause symptoms of vapor lock? It seems the opposite (if there is one) would be true, altho I don't know much in that area...I just know it runs like crap- weak idle, gets hot quickly (temp gauge ok, tho) and keeps me stranded at home! 

Any suggestions? 
Also- I finally read the codes off the ECU- lot of good that did! "55- no malfunction" ! HA!


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## jserrano (Oct 27, 2004)

I doubt it is vapor lock related. If it idles bad then you might have a cylinder that is causing an engine miss. That will cause high levels of unburnt fuel to reach the catalytic converter and kill it. If you listen to the tailpipe sound you should be able detect the sputtering. Is it a consistent sputtering noise or it inconsistent?

The idea is to do an engine balance test to track down the cylinder. Then try to isolate the ignition misfire to the ignition, fuel, or a vacuum leak.


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## leigh08 (Aug 9, 2005)

That symptoms could also be linked to other  Nissan parts comprising your Stanza. A visit to your nearest auto body shop or auto mechanic could surely give you the exact answer. It's also a great risk taking the matters at your own hand.


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## Darktide (Jul 29, 2004)

great risk? to what? This site was made to help DIY'ers and that's what they're doing. As for finding honest mechanics..... the truely honest ones normally are the most expensive... and a DIY person normally isn't the person with enough money to cough up for the mechanics to do the same exact tests that are being described here. *shrug*


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## JimmyG79 (Nov 15, 2021)

My check engine light came on last week and after resetting it several times, finally went to the dealer. Symptoms include rough idle when cold. So rough in fact that if you give it too much throttle it will stall out. Additionally, if the pedal is "floored", the car balks very badly and acts like it is going to stall.

The dealer said there were 3 fault codes. The first was a fuel pressure error which he interpreted to mean a dirty fuel filter. My car has 73K miles on the original filter, so I changed it. The other two codes best exhaust for 5.3 Silverado were the O2 sensor and crankcase pressure. I am not sure what the latter code was but the dealer seemed to think it was because my oil cap was cross-threaded and not sealing properly. They also found two vacuum lines off placed them in the appropriate locations.

Anyway, after the fuel filter replacement, the light came back on after about 100 miles. The fuel filter did not fix the hesitation problem either.

What I am wondering, it could be caused by a bad O2 sensor(s)? I wanted to change the fuel filter (cheapest and needed to be done anyway) hoping that would clear the O2 sensor error too. Do the above symptoms sound like an O2 sensor problem? I have never had that problem before so I have no experience to draw on. Any other things I should look at for the hesitation problem? It has a stock filter BTW.

Thanks


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