If the o2 sensor sets off the CEL, does that mean my o2 sensor is bad? Or if I reset the CEL and the o2 light does not come on does that mean it is operating correctly?
I ask this because my friend gets the CEL for the o2 sensor about once every 3 months and I am wondering if his performance or mileage might be suffering

 

well have him watch his mileage. The rear o2 sensor will not affect performance or mileage (I get 29.8+ on highway without a rear sensor at all), but the fronts will kill your mileage and performance.

I used to get 27ish overall, then after throwing a front o2 code, it slowly died to 24.5, and I thought it was time to replace them. Paid $80 shipped from oxygensensors.com for universal ones (ask for maxima.org discount). Just had to cut and splice off of old wires, pretty simple job, just let you car cool down overnight first! Burnt the F out of myself on the exhaust lol.

 

It's so tight to get at that front sensor. Any tricks or tips to get at them?

 

Do you have to drop the Y-pipe to replace the front sensors?

 

go to kragen rent a o2 sensor removal kit...

short answer...no

 

Well as for me...my o2 sensor has been going off for a year...along with my knock sensor. My performance is shot, but that's the least of my problems with this car (my front axle comes first). Anyways, you don't really need to replace the o2 right away- your car will just become a gas guzzler. The sensor is expensive anyways. Just use a screwdriver and reset the ecu for the time being if the light is annoying you.