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Can O2 sensor failure make car undriveable?

jguy66

New member
I have an 01 Grand Prix GT 3.8L displaying PO141 code, smells like fuel in oil and has used a lot of fuel just testing the car since it's off the road. It won't accelerate beyond 3-4k before dropping back down, dosen't stall though. I can give details on what I've checked but my question is this; Can the O2 sensor (post cat) failure alone create these symptoms? No other codes except there was a misfire on cylinder 3 after really giving it some gas. Too much gas caused by an O2 sensor?
 


from what ive read here the 01 cars dont like to not have a working rear o2 sensor, it could be causing over fueling. do a oil change, dont drive with gas filled oil, your engine can die from that.

id check the wires to the o2 for damage then if they look good put a new o2 in there.

check the cylinder 3 plug for damage too. it could just be tune up time for the misfire.

or, the cat could be clogged up. dumping fuel can clog the cat. clogged cat can cause misfires also. and hesitation, and no power.
 
Cheers, that makes sense. Wiring looks OK, just difficult even getting to the connection. I guess there's a tool for the rear O2? got one for the front but it's useless for the rear. So even after changing the O2 sensor I could still be having problems if the cat is blocked? After the oil change and O2 replacement and if it still runs badly, would removing the front O2 sensor remove enough back pressure to prove the cat is now blocked?
 
if you take the upper o2 out that will let it leak enough to tell if the cat is clogged.

box wrench works for the rear o2. or open end, a line wrench would work as well.

needing a tune up can also make it fall on its face. floor it and nothing happens but some sputtering and bogging.

clogged cat kinda sounds like a vacuum cleaner with a full bag when you floor it.
 
if you take the upper o2 out that will let it leak enough to tell if the cat is clogged.

box wrench works for the rear o2. or open end, a line wrench would work as well.

needing a tune up can also make it fall on its face. floor it and nothing happens but some sputtering and bogging.

clogged cat kinda sounds like a vacuum cleaner with a full bag when you floor it.

Changed the oil and it wasn't really smelling of gas, black and combustion smell, to be expected. I took off the front O2 sensor and it works! Not one hundred percent of course but the gas is still trying to get out of a small hole. So the cat is blocked for sure. I'm now wondering if the slight oil consumption I've noticed over the last few years and brown coolant (had to flush it a while back) is due to a manifold gasket leak. Getting oil in water and into chamber and that has blocked up the cat with contaminated exhaust gases and maybe ruined the sensor which has then contributed to the problem? Thoughts?
I plan on fitting in a generic type cat and clamping it in to the existing pipe work, just for ease of fitting if not cost saving. Do these seal OK?
 
oil cant mix into the coolant, but coolant can get into the oil. the brown coolant was old dex coolant. flushing it was a good thing to do.

if the o2 was causing the car run rich thats what clogged up the cat.

a walker cat would be best to use, something thats not hi flow, as those cats set off the o2 code, run rich again, 01 is a messed up year for the rear o2.
 


I will look into the Walker cat, thanks.
I don't want to have to change the gaskets if I don't have to, but I don't want to ruin another cat either. So a sensor failure can bung up the cat in say 6000kms which is about how long the CEL has been on and going heavy on gas?
I might have topped up the coolant with some green stuff a while ago which made the sludge I had to flush. I put Dex back in it. Now I read Dex isn't that good an idea either?
Thanks for the advice 'Scottydogs'
 
dex is not liked much here, most of us run the green coolant, dex is fine as long as its kept full, air makes it sludge up, and age i suppose, its only good for 5 years.
 
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