I have a 2002 subaru outback with 130,000 miles. For the last week or so it has backfiring and sputtering a little whenever I accelerate or the car is going up a slight incline and requiring more power. The check engine light has been on for over a year and when I had it checked the mechanic said it was related to the O2 sensor. Since I am tight on cash and the car ran fine I ignored it. Do you think it’s the O2 sensor or something else. I tried dry gas first–no luck. Am getting ready to try replacing gas filter. If it is the O2 sensorhow difficult is it to change. I appreciate your help and advise.
Since you’ve been driving the vehicle with the Check Engine light on, there’s no way in telling what’s causing the problem you describe. All that can be done at this point is to have the computer scanned again for codes to see if there’s other codes stored other than for an O2 sensor.
Well, ythe O2 sensor could have been performing erratically last year but if it has finally quit working altogether know that it is not an expensive item to replace. Usually @ $80. for the sensor if you go to Autozone, more from the dealer, less if you go to rockauto.com. But, unless your mechanic is okay with you handing him the new one you might have to do your own work, which can be aggravating unless you can lift the car high enough to work comfortably under it. And, that’s if it’s the downstream sensor located around the cat converter. If you don’t like crawling around the engine you just might want to let your mechanic do the job.