So ok...just had the entire exhaust replaced, because my cat was clogged. New header, new cat, and all new piping with new muffler.

Most of you know the symptons of a clogged cat....loud engine rev with no power above 3000 rpms, no exhaust tone out of the muffler, etc...

So the exhaust works get finished, and I drive away thinking all is great. Get down the road, and realize a few things:

1. Still no power above 3000 rpms
2. Still loud rev (as if something was clogged)
3. CEL pops on



So I pull the CEL code, and its o2 sensor, bank one. The shop re-used the old sensor from the manifold (which was perfectly fine before hand), and I checked all the wires and everything. It all seemed good, with no frays or tears in the heat shrink. Drove it around a little more, CEL went off for a few days. Drove to work this morning, CEL pops back on and the idle is super low and the car almost stalls at a stop. Also noticed that power is A TINY bit better when its cold out, but once everything warms up, no performance at all above 3K. Plus, when you do take the car above 3K, it sputters & jerks forward and its almost forcing itself to try and go beyond 3k.

The plugs and wires were changed about 2 months ago. The piping and cat are 100% clear, so I know theres nothing blocking the exhaust. What else could it be? Fuel filter? Fuel pump? TPS?

Any help is much appreciated. Its going back to the shop on Friday, and they're gonna look at it. So if you guys know what I might be able to tell them to look at specifically, it might save some time and energy. They're not charging me to do any diagnostics or labor. They're only gonna charge me what ever the part that needs to be replaced. So hopefully its nothing big. I'm definitely not an engine and tranny guy. Im all about the paint and body modifications, as most of you know. *lol* Thanks....

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O2 sensors are easily damaged.. if it was dropped, there is a good chance that the sensor is not reading the exhaust gases properly and is making the engine run lean. The reason you have more power when cold is the injection automatically adds more fuel when everything is cold.

 

I didnt think bad o2 sensors would cause that kind of power loss. When I say there is no power above 3K, seriously....I could get out and walk faster than the car...lol. And trying to go up a hill past 3k...Fu-Get-About-It! *haha* Plus, why would the CEL go off for a few days, and then come back on out of no where?

 

Definately bad performance and gas milage from a o2 sensor. In open-loop the car uses the o2 sensors for feedback to make sure it's burning cleanly. Our cars suck for a long time before the o2 sensor code is called.

 

So ok...bad O2 Sensor would cause the:

- no power above 3K
- Low RPM's and stalling
- No exhaust tone/sound out of the muffler
- Engine working extra hard to push exhaust out
- Throw a CEL, go off, then come back on a few days later


*lol* Just want to make sure I have all the basics down of bad sensors, for when I take it to the shop. I'm 110% positive that nothing is blocking any part of the exhaust components what so ever (ever single damn piece is brand new now...haha).

Thanks everyone....

 

well, here is a thought.. all the parts are brand new... how new? have they been sitting around the shop for a while? I could just see a mouse or something setting up camp in your muffler before it was installed

 

Yup...everything is BRAND BRAND new, exept the o2 sensor, which is the old one. *lol* smile.gif

 

you could be running rich. If your o2 sensor is reading lean, your car will run rich. It can cause bog and ruin your new catalytic converter too.

 

Open loop is when the ecu is NOT using the o2 sensor for feedback, strictly using the given place on the fuel map with no "trimming"

Closed loop is when the ecu is adjusting the fuel based on the readings received from the o2 sensor.

Think open switch (lights off) and closed switch (lights on).

 

^^ closed loop runs strictly on o2. open loop uses it for feedback to make sure you are not leaning out too much.

I read that somewhere. It is there so you don't burn too much fuel and clog the cat if something else goes wrong. I can't remember where I found it though.