Thanks in advance for anyone that can help me with this one, it has had me banging my head on the wall for months.
I have been having an intermittant problem that makes no sense.For months now the truck will run fine, then all of a sudden be unresponsive to the pedal.Idles rough and will not accerlate until the pedal is pushed almost to the floor.Acts like a throttle postion sensor, but all i ever get is a P0158 code, o2 sensor, downstream right bank.After I clear the code, it acts fine.
then yesterday it threw a fault code for the throttle postioin sensor, this made sense to me.I replaced it and the truck ran fine all day.This morning we are back to the same thing, truck responds poorly to the throttle and a 0158 but no engine warning light this time.
What gives?Can an o2 sensor be intermittant like this?There are no visible problems with the wiring, I checked everything.Once the code is cleared, it acts just fine.Anyone got any ideas?
Thanks!

 

You could try cleaning the sensor really good with a can of sensor cleaner from Advance/Autozone/Napa.

What is the exact wording of the code?

 

The exact wording of the code is "Downstream o2 sensor circuit high voltage, right cylinder bank"

The thing that really has got me concerned is that according to my book, a fault code from the downstream sensor should not affect the running condition of the vehicle.But, when I clear the code it runs fine.And when it throws the code, the engine warning light does not come on.

 

The down stream (And by downstream I'm assuming it's the rear sensor) O2 Sensor monitors oxygen coming out of the catalytic converter, and does not have a huge bearing on the ability of the engine to run. So yes you are correct. But make sure it is indeed the rear most O2 sensor, it should say bank 1 or bank 2, sensor 1 or sensor 2. Like Bank 1 sensor 1, or Bank 2 Sensor 1, etc. Is it's the O2 sensor after the cat having a high voltage means there is a lot of oxygen coming out of the cat, which could mean your cat is going bad, which WOULD cause the truck to run like crap.

If it's the O2 sensor before the cat then a high voltage there would indicate something with the engine. I can't remember exactly what would cause a high voltage situation, but I could look it up and get back to you if someone else doesn't chime in first.

 

If it was the cat going bad, why would it be an intermittant problem that goes away after you clear the code from the ECM?
this is what puzzles me,like you said the sensor after the cat has little bearing on the running condition of the engine, this is what has got me so puzzled.It not only the intermittant problem, but the fault code indicates a problem that really shouldnt have that much bearing on how it is running.

 

^^ I understand what you mean, and I'm not really sure what that could be. But based on the problem, I don't think it's an O2 thing. I think the O2 is sensing a problem elsewhere. Best thing I can say is try cleaning all the O2 sensor's, ensuring they are all functioning properly and if your still getting a code, start working back. Seeing what could be wrong that would cause a high voltage on the 02.

 

Thats the problem that I havent come up, what else it could be.If it was a problem further up the exhaust that was tripping the O2 sensor, then reason tells me that it should also be tripping the sensor in front of it. Every time the truck dogs out, I check with a scan tool, and the result is the same.Just the second sensor trips.Makes no sense to me at all, especially since the second sensor is not supposed to have any effect on the running condition.anyone else have any ideas?