Sudden Loss Of Power

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DAWG NATION

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Hi Guys

So, my T4R has been driving like a dream.
Yesterday i made a quick stop at the store, returned and the truck would not start.
The negative battery terminal had come loose and after i tightened it she started first time.

Problem is i noticed a drop in power (Acceleration) right away, also the gears
weren't shifting smoothly. You just know when something is wrong.

Got home and check engine light was on, tested with OBD ii and error code P1135 detected. I installed a new O2 sensor in Jan (Not Denso).

Could a faulty O2 sensor cause what i described above?

Thanks
 
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yes a faulty O2 sensor can cause a loss of power along with other problems such as reduced MPG, rough idle, etc. as you probably know your O2 sensor reads the level of unburned oxygen in your exhaust, sends that info to the ECU which then makes changes to your air/fuel ratio depending on if the engine is running rich or lean. when the sensors fail, the ECU cannot properly adjust the air/fuel ratio over the dynamic operating range of the engine, which is why you can see a loss of power and fuel efficiency when one of these sensors fail. same kinda thing happens when any sort of emissions-related sensor/ part fails (MAF, EGR, etc) since they constantly send data to the ECU to ensure the engine runs properly, so when one of these systems fails, it can significantly affect how your motor runs. kinda like taking a blind mans walking stick. hope this helped
 
Cheers .... I thought the same just looking for some reinforcement...
I did install an aftermarket O2 sensor not a Denso so it makes sense that it's failed...


lord rigatoni said:
yes a faulty O2 sensor can cause a loss of power along with other problems such as reduced MPG, rough idle, etc. as you probably know your O2 sensor reads the level of unburned oxygen in your exhaust, sends that info to the ECU which then makes changes to your air/fuel ratio depending on if the engine is running rich or lean. when the sensors fail, the ECU cannot properly adjust the air/fuel ratio over the dynamic operating range of the engine, which is why you can see a loss of power and fuel efficiency when one of these sensors fail. same kinda thing happens when any sort of emissions-related sensor/ part fails (MAF, EGR, etc) since they constantly send data to the ECU to ensure the engine runs properly, so when one of these systems fails, it can significantly affect how your motor runs. kinda like taking a blind mans walking stick. hope this helped
Click to expand...
 
lord rigatoni said:
yes a faulty O2 sensor can cause a loss of power along with other problems such as reduced MPG, rough idle, etc. as you probably know your O2 sensor reads the level of unburned oxygen in your exhaust, sends that info to the ECU which then makes changes to your air/fuel ratio depending on if the engine is running rich or lean. when the sensors fail, the ECU cannot properly adjust the air/fuel ratio over the dynamic operating range of the engine, which is why you can see a loss of power and fuel efficiency when one of these sensors fail. same kinda thing happens when any sort of emissions-related sensor/ part fails (MAF, EGR, etc) since they constantly send data to the ECU to ensure the engine runs properly, so when one of these systems fails, it can significantly affect how your motor runs. kinda like taking a blind mans walking stick. hope this helped
Click to expand...
Well said and welcome aboard!
 
Loose negative battery probably cut power to the ecu forcing default factory fuel maps. Give the ecu some time/miles to relearn it's new fuel map.
 
So I am trying to track down the reason for a rough idle. Checked all my plugs yesterday that I replaced 5k miles ago and they were all black. Checked online that color indicates that I could be running rich. Air filter is clean, MAF cleaned, TB cleaned, and I am not getting any codes. First thought is bad fuel pressure regulator but now I think I want to check out my o2 sensor. Not sure if it's ever been replaced. Is there a way to check to make sure it is working properly? Or can it be cleaned like a MAF?
 
phattyduck said:
If you suspect it and its more than 100k miles old, just replace it. It is almost a maintenance item anyway.

-Charlie
Click to expand...

Copy that thank you. I'm not sure how old it is but I've had this rig for about 15k miles and I don't recall the pervious owner saying he replaced it. Denso 234-9002 is about 125 on amazon which isn't a bad deal.
 
phattyduck said:
If you suspect it and its more than 100k miles old, just replace it. It is almost a maintenance item anyway.

-Charlie
Click to expand...

Charlie, would you consider replacing O2 sensors based solely on age, or is mileage more determinative? Mine only have about 20k miles on them but it's been nearly 7 years.
 
beklemmung said:
Charlie, would you consider replacing O2 sensors based solely on age, or is mileage more determinative? Mine only have about 20k miles on them but it's been nearly 7 years.
Click to expand...

I know I'm not Charlie for here's some food for thought. On the 2nd Gen 4Runners that use the older narrowband O2 sensor (same relative design as the 96-00 federal emissions 3rd Gens) the O2 sensor was a maintenance item to be replaced every 90K miles. I've sticked to that schedule on my current 4Runner and it's been a good guideline. Just remember we have 2, but they only cost around $45.
 
[MENTION=115347]gamefreakgc[/MENTION] Thanks, as one of the more ignorant members of this forum I welcome all input! I guess a more direct way of stating my question is whether the O2 sensors should be replaced solely based on mileage, or if time/age should also factor in to the decision. Mine don't have many miles on them, and my truck is running fine, but I'm going to have access to a garage in January and trying to put together a comprehensive plan and get everything bought to hopefully get PM squared away for a long time to come.
 
beklemmung said:
[MENTION=115347]gamefreakgc[/MENTION] Thanks, as one of the more ignorant members of this forum I welcome all input! I guess a more direct way of stating my question is whether the O2 sensors should be replaced solely based on mileage, or if time/age should also factor in to the decision. Mine don't have many miles on them, and my truck is running fine, but I'm going to have access to a garage in January and trying to put together a comprehensive plan and get everything bought to hopefully get PM squared away for a long time to come.
Click to expand...

Since you only have roughly 20K miles you should be fine. The main thing that kills the sensors is carbon build up on the platinum later inside the sensor. Age won't affect that, only miles as a vehicle that's sitting and not being used won't collect carbon. The second most common issue is the heater circuit failure due to wiring degradation. Can't really prevent that but it's an all or nothing thing so if you aren't throwing a code for the heater circuit your sensor is good.

I have "refreshed" and O2 sensor by soaking the lower half in a solution of pure acetone. It took off a lot of carbon and gave me better readings and prolonged the age of the sensor by around 6 months (it was failing). You could do that if you want, but normally a 20K old sensor will have little carbon and be good to go.
 
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