[Draughtsman]

Hey all. Long, multi-part question here. Consider yourself warned. Still, I appreciate any help.

1) I recently replaced my upstream O2 sensor after getting a CEL. Since then, it's intermittently idled roughly, as well as what seems to be slow throttle and jerky acceleration. I'm guessing these may be related, but is this normal? Does it fix itself, or is there follow-up work that needs to be done. Additionally, the CEL had gone off after the upstream sensor was replaced, but not it's back on. What are the chances it's the same issue?

2) Looking at replacing my downstream O2 sensor if the CEL doesn't go off after tinkering with the upstream one. The problem is, I haven't been able to find any good guides for my AWD car, only the FWD, and the O2 sensor connection is in a different location (FWD has it connecting in the front console, where the AWD seems to be under the front passenger seat somewhere). Can anybody give me some direction so I don't have to rip out all of my carpeting to find the connection?

3) Probably a stupid question, but can I clean spark plugs? I replaced mine last summer, and my O2 sensor CEL has been on since shortly after then. They're dirty from being run with a rich fuel/air mixture, but they're good ones, and I don't want to buy new ones if I don't have to. Thanks much.

2005 Toyota Matrix XR AWD, 175,xxx miles as of 10/2016.

 

[mikered30]

Did you disconnect your battery when you replaced your sensor? What was the CEL?

 

[Draughtsman]

Did you disconnect your battery when you replaced your sensor? What was the CEL?

Yep, disconnected the battery. That's how the CEL went off after the first sensor change-out. I had the CEL ran at an O'Reilly's, so it was a generic code, including but not limited to: gas cap, oxygen sensors, maybe a gasket or vapor lock issue... I started with the cheap and quick fixes first.

 

[cj1]

"Additionally, the CEL had gone off after the upstream sensor was replaced, but not it's back on."
If CEL is back on with same error code then similar issue exists.
Can you post the error code?

 

[75aces]

You could try replacing the intake gasket to improve the idle. Try driving the car around and see if the computer clears the code. The cat may not have enough heat to clear the code.the computer is detecting something with hc or NOx.

 

[Draughtsman]

UPDATE

Can you post the error code?

CEL was off this morning, but came back on this afternoon. Swung by an O'Reilly's and used their diagnostic tool, and it spit out the following:

-P0133, Generic, O2 Circuit Slow Response (Bank 1, Sensor 1)
-P0172, Generic, System Too Rich (Bank 1)
-P0130, Generic, O2 Circuit (Bank 1, Sensor 1)

Bad sensor out of the box? Bad connection? I'll try disconnecting and reconnecting the sensor, using some dielectric grease this time.

Try driving the car around and see if the computer clears the code.

I changed the O2 sensor last weekend, so we're going on about a week of highway and city driving. Does it normally take this long to clear the code or recalibrate the computer? The code disappears and reappears intermittently, with no apparent relation to outside temp, engine temp, driving time, driving speeds, etc...

I'm hoping not to have to replace the intake manifold gasket, but that and the MAF are next on the list...

 

[75aces]

UPDATE

Can you post the error code?

CEL was off this morning, but came back on this afternoon. Swung by an O'Reilly's and used their diagnostic tool, and it spit out the following:

-P0133, Generic, O2 Circuit Slow Response (Bank 1, Sensor 1)
-P0172, Generic, System Too Rich (Bank 1)
-P0130, Generic, O2 Circuit (Bank 1, Sensor 1)

Bad sensor out of the box? Bad connection? I'll try disconnecting and reconnecting the sensor, using some dielectric grease this time.

Try driving the car around and see if the computer clears the code.

I changed the O2 sensor last weekend, so we're going on about a week of highway and city driving. Does it normally take this long to clear the code or recalibrate the computer? The code disappears and reappears intermittently, with no apparent relation to outside temp, engine temp, driving time, driving speeds, etc...

I'm hoping not to have to replace the intake manifold gasket, but that and the MAF are next on the list...

At this point, it can be a combination of things. If the scan tool notes running rich, then try cleaning you maf. The computer is trying to compensate by advancing the timing and that's why it's rich. it's possible you got a bad part, although, it can be something else. Generic code to me means that the computer isn't able to pin point the source. clean your maf and go from there.

 

[cj1]

P0172 indicates, if sensor good, mixture is rich. As has been noted MAF could be over reporting and cleaning may help.
Sensor was replaced with a OEM such as DENSO #2344801?

 

[hardtopte72]

FWD and AWD models use different oxygen sensors.

What was the part number for the sensor? It sounds as if you used a FWD sensor based on your immediate issues.

 

[chrisboyd]

I just had this same issue when replacing the rear O2 sensor on my '06 Matrix. I pushed a thin pick up through the carpeting to locate the entrance hole inside the cabin. Move the passenger seat all the way forward. The hole is located about 6" to the rear of the air outlet under the seat, near the center floor hump. I cut a small slit in the carpet, just where the floor meets the center hump, and located the blue-white-black wires. Tracing forward, I then realized the connector is right under the edge of the carpet to the center (driver's) side of the air outlet.
I still needed help from the small slit I made to feed the new connector and wire up from below and under the carpet to the opening near the air outlet.
I am sure there is a way to pull the carpet back enough to do it without cutting the carpet, but I already had the cut made, and it's a 12 year old car with over 200k on it.