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?

[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?