Slow Acceleration and P0125

[bergeron37]

I apologize in advance if this question has been answered but so far in my searches, I haven't found an exact answer for my issue. I have a 98 5VZ-FE (V6) with 207k miles on it.

Over the weekend, I hit a pothole getting off the highway and immediately felt something go wrong. I started hearing a loud noise coming from the front passenger engine compartment on acceleration. Now, I am experiencing significantly decreased acceleration but there isn't any change to the RPMs.

The next day i threw a P0125 code and I know these are tricky to diagnose (A/F sensor usually). In reading everyone else's experiences with that code, I have not seen anyone mention the slow acceleration issue that I am having. I'm going to have to take it to a shop to have the work done but I'd like to be able to tell them exactly what I think is wrong in advance

 

[shootmymime]

I apologize in advance if this question has been answered but so far in my searches, I haven't found an exact answer for my issue. I have a 98 5VZ-FE (V6) with 207k miles on it.

Over the weekend, I hit a pothole getting off the highway and immediately felt something go wrong. I started hearing a loud noise coming from the front passenger engine compartment on acceleration. Now, I am experiencing significantly decreased acceleration but there isn't any change to the RPMs.

The next day i threw a P0125 code and I know these are tricky to diagnose (A/F sensor usually). In reading everyone else's experiences with that code, I have not seen anyone mention the slow acceleration issue that I am having. I'm going to have to take it to a shop to have the work done but I'd like to be able to tell them exactly what I think is wrong in advance

po125 is a closed loop fuel malfunction code. essentually your truck has a few sensors (coolant temp, air fuel, o2) that is reading the temp of the motor and exhaust leaving the motor. well one of the sensors is not matching with what the others are showing.

when you start your truck in the morning (cold engine) the egr valve opens to let exhaust gas back into the intake to help warm the motor up faster. there are time parameters set by toyota to tell the truck if it does not match these reading by this time something is off. thus the code.
[MENTION=92884]snivilous[/MENTION] asked my about this same problem he is having with his truck as we speek.

the way to diagnose it is to check if there is another cel and fix that one first.
as an example i had a p1301 (air fuel heater sensor go bad and it also set a po125 code) by fixing the a/f sensor it get rid of the po125, now i can not clearly say that your problem is the same as mine because like i have said there are other sensors associated with this code that could be at fault.

Ill keep looking into how this works.

 

[bergeron37]

Thanks for the response. I think what sets my issue apart from others here is the fact that I can pinpoint an exact cause which led to the slow acceleration/CEL.

As soon as I hit that pothole, it's almost as if a hose came loose leading to the catalytic converter. I'm trying to find a diagram of the exhaust system so I can find out what would be located in the area where the noise is coming from (near the firewall on the passenger side).

 

[shootmymime]

Thanks for the response. I think what sets my issue apart from others here is the fact that I can pinpoint an exact cause which led to the slow acceleration/CEL.

As soon as I hit that pothole, it's almost as if a hose came loose leading to the catalytic converter. I'm trying to find a diagram of the exhaust system so I can find out what would be located in the area where the noise is coming from (near the firewall on the passenger side).

go open the hood and just start looking around. look under the truck.

 

[bergeron37]

Found the culprit, knocked the O2 sensor right out. I can just bolt this back into place, correct? Anyone know the size bolt I need or if there is anything else I need to know. Sorry for the dumb question...

 

[TheDurk]

Unless it is stuck to the bung, you are missing the ceramic gasket that should be there--and it needs to be pressure tight or codes won't stop. It was not held on with bolts, but stainless nuts on studs (M8-1.25) If the studs are gone, I believe you can go to bolts with some drilling and tapping, but I haven't done it. [MENTION=56021]Nelsonmd[/MENTION] has, I believe.

 

[MONTYMTB]

Since you have a '98, I'm assuming it has just one cat. If so, and you want to replace that sensor, get this one: http://www.amazon.com/gp/product/B000C5UFK8/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1
Same maker as OEM, but much cheaper.

 

[Nelsonmd]

eep: wha... I heard my name called...

I think those are M6 studs that hold the O2 sensor in (not sure, so just grab a couple size packs from autozone and return the ones you don't use). See what your studs look like. Since you're in Boston they are probably rusted to hell and the nuts are just gone, hence why your sensor fell out (BTW, this same thing happened to my pastor, his nuts were completely gone)[EDIT: just read this again, try to control yourselves fellas... keep it classy]. So you will need to clean off the studs before putting new bolts on there. You can get a new gasket from amazon, or maybe even Vatozone.

Get that thing mounted back up and your codes should go away (may take a little driving for them to go away). Should be an easy fix.

I wouldn't replace the sensor unless you have to, in which case you should reference the URD chart for the PN.

Where in Boston are you?

 

[bergeron37]

eep: wha... I heard my name called...

I think those are M6 studs that hold the O2 sensor in (not sure, so just grab a couple size packs from autozone and return the ones you don't use). See what your studs look like. Since you're in Boston they are probably rusted to hell and the nuts are just gone, hence why your sensor fell out (BTW, this same thing happened to my pastor, his nuts were completely gone)[EDIT: just read this again, try to control yourselves fellas... keep it classy]. So you will need to clean off the studs before putting new bolts on there. You can get a new gasket from amazon, or maybe even Vatozone.

Get that thing mounted back up and your codes should go away (may take a little driving for them to go away). Should be an easy fix.

I wouldn't replace the sensor unless you have to, in which case you should reference the URD chart for the PN.

Where in Boston are you?

Thanks for the responses guys. I am definitely going to try and just get this one mounted back up instead of buying a new one. It was without-a-doubt caused by rust and I'm not afraid to admit that the undercarriage is pretty rusty but what else do you expect for a 16 year old car with 207k miles that has spent its entire life in the northeast?

I want to do this myself as it seems pointless to take to a garage. Unfortunately I probably wont be able to do it until Saturday morning due to work.

Nelson - work in Bridgewater, grew up and still live in Westwood. I am a lifer to the Boston area (besides college in Providence) and don't ever see myself leaving.

 

[Nelsonmd]

Thanks for the responses guys. I am definitely going to try and just get this one mounted back up instead of buying a new one. It was without-a-doubt caused by rust and I'm not afraid to admit that the undercarriage is pretty rusty but what else do you expect for a 16 year old car with 207k miles that has spent its entire life in the northeast?

I want to do this myself as it seems pointless to take to a garage. Unfortunately I probably wont be able to do it until Saturday morning due to work.

Nelson - work in Bridgewater, grew up and still live in Westwood. I am a lifer to the Boston area (besides college in Providence) and don't ever see myself leaving.

Oh nice, I work in Attleboro. You're just down 495 a few exits.

 

[TheDurk]

eep: wha... I heard my name called...

I think those are M6 studs that hold the O2 sensor in

I'm quite sure about the M8-1.25 for the nuts--is the back end a different size?

 

[Nelsonmd]

I'm quite sure about the M8-1.25 for the nuts--is the back end a different size?

Yeah, you're probably right, I didn't catch that in your post.