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Old 10-30-2009, 06:47 PM   #1 (permalink)
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Default Hesitation and backfires

Hello all,
I have a 2001 Outback 2.5 AT. The car has 82,000 miles and recently started hesitating while accelerating from a stop. It occasionally backfires. Iíve searched this forum and just ordered a front oxygen sensor from subarupartsforyou.com. I havenít received it yet, but i have been doing a little bit more research and am starting to wonder if it is the 02 sensor or not. The car now hesitates on acceleration and at about 3,000 to 4,000 rpm. Anyone have any ideas on what this might be?
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Old 10-30-2009, 07:53 PM   #2 (permalink)
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Mine had a very similar problem but I wouldn't call it backfiring. It was the front o2 sensor. Had 3 mechanics look at it (all of which I told to look at the o2 sensor) and none of them could figure it out. $120 and 2 hours of work later it's worked perfectly for a year now.
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Old 10-30-2009, 09:42 PM   #3 (permalink)
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Could be an O2 sensor or a knock sensor.

As an FYI you will be coming up on a timing belt very shortly, every 106,000 miles OR 106 months, which is 8-9 years.

Its a bit early for an O2 sensor but it happens. A tuneup may be a good idea too.

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Old 10-30-2009, 09:51 PM   #4 (permalink)
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Thanks for the replies. The weird thing is that the check engine light has not come on.
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Old 10-30-2009, 09:57 PM   #5 (permalink)
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Quote:
Originally posted by paweliania
Thanks for the replies. The weird thing is that the check engine light has not come on.
Not really odd, but still have the codes read, as there may be a code stored.


BTW the CEL does work?

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Old 10-31-2009, 11:35 AM   #6 (permalink)
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Yea the CEL does work. I pulled the codes yesterday and the only thing that was on there was P0302 which is cylinder 2 misfiring. But that was because I was stuck in snow the other day, and was going drive then reverse to try to get out, that is when the check engine light went on. It was not on before that. Since then I reset the CEL and it is not comming on again.
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Old 10-31-2009, 01:21 PM   #7 (permalink)
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Quote:
Originally posted by paweliania
Yea the CEL does work. I pulled the codes yesterday and the only thing that was on there was P0302 which is cylinder 2 misfiring. But that was because I was stuck in snow the other day, and was going drive then reverse to try to get out, that is when the check engine light went on. It was not on before that. Since then I reset the CEL and it is not comming on again.
So lets replace the spark plug wires with OE then.


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Old 11-01-2009, 09:45 AM   #8 (permalink)
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I had the same code. I replaced the spark plugs and reset it. I can't recall if it ever came back before I replaced the o2 sensor but since the sensor I have had one CEL and it was a p0420. Cleared it and it hasn't come back in months.
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Old 11-01-2009, 06:36 PM   #9 (permalink)
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What kind of fuel pressure do you have? Miles on fuel filter? When you say 'hesitates ... at about 3,000 to 4,000 rpm,' do you mean only in that rpm range or from that rpm point onward, you have lost power?
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Old 11-01-2009, 07:05 PM   #10 (permalink)
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The replies to your problem are generally pointing to a complete, major tune-up of your vehicle. The misfire in one of your cylinders should be fixed soon.
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