05 civic ex running poorly after o2 sensor swap

Oknva05

New Member
Hey everybody. So my girlfriend has an 05 civic ex, the upper o2 sensor failed and caused the check engine light to come on. She drove it like that for a month or so, very minor to no performance issues. I swapped out the sensor with a denso last night, and now the car is running like crap when it warms up. Rpms drop to Around 500, sputters and acts like it's gonna cut off. The plugs are old so I swapped those out but still the same. It almost seems like there is a intake or vacuum leak, and I looked around where I was working and didn't see where I would have knocked anything loose. I disconnected the battery for a few minutes to clear the computer after I swapped out the sensor. Any advice would be awesome, thanks guys
 

Oknva05

New Member
I had trouble driving it home from my friends where I swapped the sensor, The symptoms started pretty much immediately
 


Oknva05

New Member
No check engine light, my friend is bringing his code scanner now. Could there be a code present with no engine light ?
 

Oknva05

New Member
I can't drive it anywhere. It's stalling out so bad I can't take it on the road. It's fine when it's parked and idling, but when I put it in drive I have to floor it to keep it from glubbing. Like I said, I barely got it home at like 25 Mph The Whole way with the hazards on. It was a 10 min drive
 


Oknva05

New Member
Explain to me what information you would like as though I'm a child please. I will do my best to answer your question.
 

lowlife9

New Member
Registered VIP
5+ Year Member
the 04-05 civic use the more expensive wide band oxygen sensor. did you replace it with the proper sensor ??? or did you use the cheaper 01-03 civic sensor ???
 

Oknva05

New Member
I bought a Denso 234-9017, it was $83 on Amazon. I was told by a few sources that it was correct. I performed the procedure above and it's doing the same thing. I now have a p0134 and p0171 fault code, which relate to the bank one o2 sensor. I'm getting pretty frustrated lol. I'm not auto mechanic but I'm a master licensed hvac mechanic and pretty good at figuring things out. This has me stumped
 

lowlife9

New Member
Registered VIP
5+ Year Member
o2 sensors are delicate i would never buy one online. i would return it and buy one localy,its entirely possible they gave you the wrong sensor or it could be damaged.
 

Youngsoulja2

New Member
The 2005 Civic 1.7L has 3 sensors on the exhaust. The top one I believe is an Air/Fuel mixture and something about it makes it different then the regular up stream and down stream sensors. I had a similar problem with my old 2002 Civic HX. If you are talking about the sensor on the very top almost by the valve cover that is the air fuel sensor, That particular sensor when I looked at them was like $157 compared to the other 2 sensors being around $50 each.
 


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