Installing New Oxygen Sensor, I think my O2 sensor is bust Options

[soltrain]

So the celica's been having some hard times lately. I used to have this every-once-in-a-while stuttering and uneven acceleration and idling problem which has now become an all the time thing. It'll happen soon after I start the car, the engine will settle at 900 or so RPM, but then stutter every couple seconds, like it was misfiring a cylinder. Acceleration would be very jerky, especially in gears 1 and 2.

The car threw a check engine light the other day, and I did the paper clip thing to test, it was code 25 and 26, which is for fuel air ratio too rich or too lean.

I've got a 1995 GT with about 120K miles on it, and as far as I believe, it's the original O2 sensor, so I'm guessing it's that.. I think I have to replace the main O2 and not the secondary, is this also called the "front" sensor? And it's got a "flange"? The strange thing is that my mileage has not changed, and is good (30mpg highway).

Here's the part I was looking at from Denso, think it'll work? I'd rather do a straight replacement than any soldering or crimping...

http://www.densoproducts.com/more_info.asp...41&pid=2279

Also, is this what I should be switching out?

[Batman722]

the top one.

[DEATH]

x2. The top one is also way easier to change than the bottom one [For the bottom one I would suggest using the correct tool to change it as it has very weak flats that strip easily]. Be careful with the nuts when you take it off - they've gotten incredibly hot many many times.

[soltrain]

Augh! I replaced the primary O2 sensor and still have the acceleration problems. Any suggestions on next steps? Fuel Injectors?

[Remy]

Augh! I replaced the primary O2 sensor and still have the acceleration problems. Any suggestions on next steps? Fuel Injectors?

I would replace my fuel filter (If it wasn't replaced yet...) and maybe throw in some FI cleaner. I had the same problem and thats what fixed my problem but then that was just my car I can't guarantee that it'll fix yours but with the exp I have it could be alot of other things too like spark plugs, bad grounds, etc....

[MSKapcala]

So the celica's been having some hard times lately. I used to have this every-once-in-a-while stuttering and uneven acceleration and idling problem which has now become an all the time thing. It'll happen soon after I start the car, the engine will settle at 900 or so RPM, but then stutter every couple seconds, like it was misfiring a cylinder. Acceleration would be very jerky, especially in gears 1 and 2.

The car threw a check engine light the other day, and I did the paper clip thing to test, it was code 25 and 26, which is for fuel air ratio too rich or too lean.

I've got a 1995 GT with about 120K miles on it, and as far as I believe, it's the original O2 sensor, so I'm guessing it's that.. I think I have to replace the main O2 and not the secondary, is this also called the "front" sensor? And it's got a "flange"? The strange thing is that my mileage has not changed, and is good (30mpg highway).

Here's the part I was looking at from Denso, think it'll work? I'd rather do a straight replacement than any soldering or crimping...

http://www.densoproducts.com/more_info.asp...41&pid=2279

Also, is this what I should be switching out?

Is the top one the "upstream" O2 sensor and the lower one the "downstream" O2 sensor? If not, what is the lower sensor? Are these the only 2 O2 sensors?