No o2 sensor, no CEL, bad sign?

[s13EastTN]

Well I was polishin my valve cover today and noticed my o2 sensor wasn't hooked up. But I haven't had any CEL or any power loss that I can tell (only had the car 25 days). Is it a bad sign that I haven't had any cel lights even tho this was unplugged? Or do I have to turn the screw on the ecu to make it show up?

[Fenvy]

maybe it was some how bypassed? or the cel led was removed purposely? try to trigger some CEL yourself to make sure it's working

[wangless]

turn the key to the "on" position... most of your little dash lights should light up... including the CEL.

[s13EastTN]

dash light comes on, car runs better now @ least. Maybe i just didn't see the light if/when it came on?

[Fenvy]

turn the key to the "on" position... most of your little dash lights should light up... including the CEL.

no... my doesn't turn on

[s13EastTN]

Mine does, might wanna look into yours.

[wangless]

yeah Loveless, you might wanna check on that bulb of yours...

[240dreams]

will not running a o2 senor decrease gas mileage? i have an SR but the wiring was a lil confusing and i dont even know if the 02 sensor is working or not. im getting about 250miles to a tank. no CEL either.

[s13EastTN]

I would imagine it would cause a loss of gas mileage, loss of power, change in exhaust note, and a rougher idle. @ least I got better mileage, more power, better exhast tone, and a smoother idle once I hooked it up, so it can't be bad to have one.

[WeldingHank]

i have never seen my CEL...not even when the key is in the ON position with the car off. i thought maybe it was a nissan thing as i didn't know anythin about them. maybe i was wrong.

[Dattebayo]

the idle should be alot higher, like 1200 rpms, if the O2 sensor is not hooked up or not working. The engine may cut off suddenly while driving (between shifting gears or any sudden drop to idle) or a strong gas smell may emit from the tailpipe.

[240dreams]

i dont get any of the above except a strong gas smell and bad mpg (16 mpg). i guess i need to change the o2 sensor or something.