how do i determine if they are going bad. what are the symptoms?

my car seems to "choke" when i punch it. it doesnt do it all the time. i had a guy said it might be my O2 sensors that are bad. my car has about 130k miles on it and i havent changed them before. it also smells like gas all the time. im guessing its running very rich.


the wires and plugs are new.

 

Check your fuel pressure ....mine did that for the longest and the reg was bad. I was only gettin 26lbs. When the presure is that low it will seem like its running rich but its because it doesnt have enought pressure to the injectors to make the fuel atomize like it should.
If thats not the prob good luck with it.

 

thanks for the info. ill check that out.
thanks
michael

 

If your car is running rich all the time, that can easily damage the 02 sensors.

 

I think that I am having this problem too, my car smells like gas when I start it. The check engine light came on and I had it diagnosed, The diagnosis said that both fuel banks are running rich.

What should the fuel pressure be and how should I check it. I really want to fix this before I ruin my O2 sensors.
I am running fuel injector cleaner right now.

Any advice would be nice

 

Fuel pressure should be 41 - 47 psi at idle with the vacuum line removed from the FPR.

130K mile O2 sensors should be replaced; as the O2's age, they get coated and this will make the car run rich.

"Punching" the car will put the PCM in enrichment mode; the O2 sensors aren't used in the enrichment mode. Check the car for knock; knock will cause the PCM to pull timing causing bogging.

 

thanks for all the info, ill check that out.
thanks
michael

keep them coming

 

I had the car scanned and it showed the o2's between 100-900 and changing up and down quickly. I believe this is normal but if they have never been changed and the car has over 100k miles is it time anyways?

 

You might want to add basic info like the year of your car to your signature. If you have a 96/97, the PCM monitors the O2 sensors switching rate ("crosscounts") and has a few other diagnostics that OBD-I does not have. In any case, a scan of the PCM should show if the sensors are responding correctly. Although the sensors are not used in PE mode (~WOT), the PCM does use what is learned in closed loop and it may be adding an excessive amount of fuel at WOT, depending on whether the O2 sensors are reporting a rich or a lean condition.

 

ok i know this is an old topic but since i didnt want to start my own for a simple question here it goes, i believe i need a o2 sensor and the guy at autozone told me that if i replace one of them the rest will go bad in time and it would be best to buy all of them at the same time. Is that true or just coincidence that they need replacing around same time cuz mainly cars age and sensors age. My car only has 72k on it and its a 96