The "Service Engine Soon" light came on a few days ago in my '03 G35 Sedan A/T. I took it to Advance Auto Parts and they scanned it and said it needed an O2 sensor. The problem though is that there are 3 sensors. The car has a little over 90k, so I assume this is normal?

I'm going to replace all 3, retail price is $130 a pop, but I'm getting a deal at $80 a pop. We've noticed that the gas mileage has dropped a bit in the last couple months, so hopefully this will fix that problem too.

While I'm under the car, I'm going to put on the coupe mid-pipe I picked up. But I really just wanted to see if anybody else has had to do this yet.

 

I've read of a couple of ppl here that have replaced failed O2 sensors already. Usually good practice to replace all of them anyway, especially if you're getting a good deal.

 

one goes...Replace them all.