Ok, so I've owned my 2000 RS for 1.5 years. I've just replaced my third o2 sensor on my car. The only thing I have is a Rampod Cold Air Intake. Is there anyway this o2 constant failure is caused by the CAI? Or is there a Subaru Part issue with the o2 sensor that I am unaware of? Also my dad's an auto mechanic, and he's talked to some guy that have said the following. They say that after the first o2 sensor goes, it reprograms the ECU causing the ECU to make the other o2 sensors go bad. This last one lasted just under a year. I dunno i'm trying to rack my brain (and now all of yours) to find out what the issue is.

I dont know what guy your dad talked to but that is not remotely true

Yes subaru had a problem with the front o2 sensors, there was a recall on the 00 RS.

Since you havent had the car that long, you should be having to pay for the 02 sensors, only the first one, each sensor has to carry 12k 12month warranty, so they should be being replaced for free, as long as your dealer doesnt care about the intake.

Do you use good gas?

How many miles on your car.

Jay

Yeah, I keep sending them back because of the warranty. I use regular gas at a gas station with a known name (nothing privately owned). And I currently have ~ 64,000 miles on my car.

What's your gas mileage like when the O2 sensors are still working? How long before they foul?

Lots of black soot from the tailpipe?

When the o2 sensors are working, I get 30 miles to the gallon highway, and like 25 around town. I've gone through 3 in the past year. I've also driven ~40k miles in the past year. And I hear its running rich sometimes from people driving behind me.