My car has been running rich for some time now. It chugs on acceleration really bad. I hooked it up to a code reader and it said I had a bad o2 sensor so I replaced it. Still have the same problem. I hooked it back up to the reader so see what mV my 02 was reading and it was staying at 1107. I'm not sure if this is a failsafe or a limp mode of sorts but I can't seem to pin point my issue. Any thoughts?

Might be a wiring issue if a new sensor throws the same code.

I had a TPS sensor issue. The +5v coming from the PCM no longer consistently provides the 4.5-5v required. I actually ended up jumping that supply from the MAP sensor after running a new lead from the pcm and having that not work.

I would test the PCM side of the connector and make sure youre getting the proper volts and connectivity that you need there.




"A car just isn't a car without a little blood, sweat, and beers." -- Shadowfire

Well one very important thing we are missing is which sensor is it? That is very important, assuming its the one after the cat or ( Bank 1 sensor 2 ) ( Which is usually the one that gives milivolt (mv) readings that high. Could be several things, here is what I want for you to do... assuming the code reader has a live data section, start the car up and look at sensor one and two and I want you to post the numbers you have. What I really want to know is what is the average reading for the first sensor? In a perfect running system even with a bad Cat, sensor two can never be higher than sensor one. Also tell us what exactly the code is that you're getting? Is it high circuit voltage? Heater circuit issue? ..... Lets start with that and we'll pic up on our diagnosis

It is bank one sensor one. It's the one before the cat. On the live feed it is reading 1107 mv constantly. Never fluctuates. Even with the sensor unplugged it reads the same. The code says bank one sensor o2 high.

What I'm thinking is that you're circuit may be shorted to power somewhere, so I'm with Matt there must be a wiring issue somewhere. When you look at your live data again check your short term and long term fuel trim and give us those numbers. A normal fuel trim should be between -5 and +5 ( In my opinion but officially its + or - 10 ) Fuel trim in a sense is to addition or subtraction of fuel by the ECM to make the car run properly. So lets say you had a vacuum leak and your car was getting more air than it was supposed to. Well at that point your car would be considered running "Lean" so your fuel trim would go up depending on how big the leak was, if the leak was big enough it could go all the way up to +21 to keep the car running smoothly. Vice versa if the vehicle thinks its running rich because of the reading its getting from the O2 sensor ( Which we know is false ) Then its possible your vehicle is trying to pull back fuel to compensate the rich condition, So the fuel trim would read - and how ever severe it was could be -15. So at this point we have our Cavy pulling back gas for no reason so your air fuel mixture is off because there is no rich condition in the first place. Everything is normal, So the car is trying to make up for a problem, but since there was no problem initially thanks to that lying a** sensor, well shucks now the car is making one. Which I believe could be why its jerking , but thats just a hunch. Take a picture of the live data readings and we can go from there.

Give me the specific codes that you have? All codes and if you can give us pictures of your live data that'd be super awesome ... I promise bro we're going to figure this out, then celebrate by grabbing us a couple of fat girls

Right now at idle I'm not getting a reading at all on short term or long term trim. It's just 0 on the feed. My o2 b1-s1 I'm getting the same 1107 as before. The sensor after the cat is reading around 91 at idle. My air fuel is reading 14.0 all the time and it threw four codes. O2 signal high bank 1 sensor 1. 02 heater crkt bank 1 sensor 2.
02 sensor fault bank 1 sensor 1 and heater crkt bank 1 sensor 1. That's what I have right now

bro give me the year of the car and the code numbers you're getting. Also you said sensor 2 was at 91mv at idle? Is that where it sits or does it fluctuate?

And as far as your short term and long term fuel trim goes, you stated that they are both at 0? When you say that do you mean they are fluctuating or are they really just sitting at 0? I'm not trying to be funny or anything, but when you did the live data scan you did have the car running correct?

Ok so I put my car on the lift to just check everything out and look for stuff out of place. It turns out somehow the front and back o2 sensors were just hooked right to each other. And the correct connectors were hooked to each other as well. I hooked it all back the way it should be and it runs pretty well now. That was the reason I was getting no input day and it was making the car wayyyyyy rich

Hey man I'm happy everything worked out for you. Nothing like a FREE repair to make things good as new lol, Bro when you get free this weekend grab you a couple of fat girls..... you earned it

Already got some lined up😎