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illapino wrote:should i replace the exhaust pipes that the new oxygen sensors will go into, or can i get by with just replacing the o2's on my 230 000 k car ? (just a new-part-with-old-part concern, know what i mean?)

no need - unless the pipe is completely rusted out and one step away from leaking.

well i don't know where u got 2 sensors for under $50, but the best Denso I can see is the one above, only one rear, for $150 US ... and what's with 3-wire and 4-wire? i take it that i should get sensors with the connector attached right? seeing them for sale without a connector scares me because they look like a permanent invitation for me to do some soldering ... so which is it? 3-wire or 4-wire ?????? (Precidia GS V6 24-valve)

It depends on which of the 3 o2 sensors you mean (i think you were talking about the rear one. Some of them have 3 or 4 wires.

You can look up your old o2 sensors and count how many wires they have - i am guessing it should be either 3 or 4. There is not a whole lot of difference between them - 4 wire type just has an extra wire for signal ground (in addition to 2 heater wires, 1 signal wire). The universal (cheap) sensors come with crimp on connectors - so no soldering is necessary - you just have to cut the sensor off from your old connector and crimp in the new one (after figuring out the wire colors).

Just to add my 2 cents, I had codes from both of my o2 sensors.I suspected bad plugs and wires so I changed them, cleared the codes, and they never came back. Bad plugs were causing my o2 sensors to give an inversion error. I would suggest that before you spend a lot of bread on something you may not need, clear the codes and see if they come back. If they do come back, you may find that a rich or lean condition (in my case rich) may be causing the codes and not the sensors themselves. Just my thought on the matter.

hate this old car ... how can i appreciate something that keeps on being such a nitty-picky ...