i got a 2000 civic si and it doesnt have an o2 sensor!! could it cause my lumpy idle and stuff?

 

No O2 sensor makes the engine run rich, which can cause many problems.

 

A stock ECU must have an O2 sensor (actually 2, but you can use a "simulator" to fool it on the second one, not the first though). Maybe some of the "chipped" setups can run without one; don't know anything about those.

 

I have a question about the 02 sensor. I have the 05 reverb and the check engine light keeps coming on intermittently and drives terrible when its on. I had it scanned and got the code but the garage didnt know what the issue was. I called the dealer gave them the code and they said that its new software that needs to be installed for the 02 sensor. Has anyone heard about this and if so can it be done anywhere else other than the dealer?

 

Only a dealer can do it, but they should upgrade the software for free. It's a TSB / recall issue.

 

If u don't have a o2 sencer ur PCM can't tell how much of what emmisons is comin outta the combustion chamber.. And can't tell if ur cars runnib lean or rich.. And if it's running to rich it could lead to a rich missfire or vis versa with it runnin to lean.. Also u can ruin ur cat like that.. I'd get it replaced as soon as possable.. And plezz don't listen to all that fool the computer bull**** and not have a second one cuz ur PCM won't b able to tell if ur cats doin it's job or not... Good luck bro, civichatchy95