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2008 Outback 2.5i 5MT Newport Blue Pearl
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21 Posts
Discussion Starter · #1 ·
Hi everyone, I don't want to beat a dead horse with the P0420 code but I want to know if anything in my situation might lead me to a different outcome than what I have read on different threads. I have a 2008 Outback 2.5i 5 speed MT.

A few months ago, my check engine light went on and flashed. Pulled up both the codes that indicated misfire on cylinders 3 and 4. The misfire was very infrequent and only happened every so often. Dealer said it needed new spark plugs and wires. I said ok do the work. Got it back from the dealer and it behaved fine for a few weeks. I was away for a few weeks as well so I didn't drive it obviously. Well check engine light has returned and is flashing, codes are still for the cylinder 3 and 4 misfire and now the P0420 code. I really don't think the cat is bad because I am getting excellent power and gas mileage when it is not misfiring. It will misfire now intermittently and then be back to normal. I have also noticed a strong gasoline smell from the exhaust, most noticeable when misfiring. I am going to replace the front O2 sensor. And then if that doesn't work then will look at adjusting fuel valves. What action do you think I should take. I really do not want to take it back to the dealer if I don't have to. Thanks for all the advice.
 

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2002 3.0 VDC Wag + 2018 2.5 Leg Ltd
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2008 Outback 2.5i 5MT Newport Blue Pearl
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21 Posts
Discussion Starter · #4 ·
So I took it to the dealer and under the SULEV warranty they replaced both catalytic converters, oxygen sensor, and air flow sensor. Bringing it home the car operated fine. I took it out later today and upon pulling out onto the main rood from my street, the car started sputtering again. Obviously misfiring. It did not throw a code though. As I was turning the car around, the check engine light flashed a few times and then shut off. I only went about a quarter mile between leaving the house and turning around. When I got home, I tried to pull up any possible codes on the dashboard and it didn't have any. I am at a loss of what it could be. Any ideas since replacing the converters and sensors didn't work? I did bring up the possibility of it being the coil pack and dealer was pretty decided that wasn't the issue. I'm thinking it could possibly be since 3&4 do share a coil and I don't want the misfiring to make this catalytic converter go bad by dumping fuel.Any ideas appreciated.

Thanks,

Kurt
 

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2005 Outback 2.5i 5spd 400,000 miles+
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8 Posts
If it was mine I'd go ahead and swap the coil, maybe do plugs and wires too if they're old or unknown when last done.
 

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2008 Outback 2.5i 5MT Newport Blue Pearl
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21 Posts
Discussion Starter · #6 ·
Ended up changing out the coil pack. Problem solved! Thanks everyone!
 

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On the Super Mod Squad
2002 3.0 VDC Wag + 2018 2.5 Leg Ltd
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Ended up changing out the coil pack. Problem solved! Thanks everyone!
hope that was a OEM coil,...even a used one that says "subaru" on it.

or maybe a NGK/NTK one.

lots of aftermarket junk coils out there for these cars. (like so bad they make people want to sell a otherwise good car).
 

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(formerly) 03 H6 OBW , (presently) 06 WRX Sportwagon & 2021 Honda CR-V
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what dealership did the work on the car?
 

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2002 3.0 VDC Wag + 2018 2.5 Leg Ltd
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updated thread title.
 

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2009 Subaru Outback 2.5i
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278 Posts
hope that was a OEM coil,...even a used one that says "subaru" on it.

or maybe a NGK/NTK one.

lots of aftermarket junk coils out there for these cars. (like so bad they make people want to sell a otherwise good car).

I second what eagleeye said. On my '09 I initially replaced a failing coil (that was causing progressively worse misfires on 3&4) with an aftermarket one from NAPA. That coil only lasted about 4 months before it started acting up and doing the same. NAPA replaced it under warranty, but I was planning on replacing that warrantied coil with an OEM one as soon as I got a chance...but I ended up swapping engines to a later EJ253 that had Coil on Plug ignition so that kinda took care of that. LOL.
 

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2008 Outback 2.5i 5MT Newport Blue Pearl
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21 Posts
Discussion Starter · #11 ·
Premier Subaru in Watertown, CT. Yes I made sure it was OEM.
 

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2017 3.6R Limited (Wifes), 2009 3.0R Limited 125k (Mine)
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241 Posts
Many dealerships and mechanics have become nothing but parts changers. They did a lot of unnecessary work to your car when all that was wrong was a failing coil. Glad you finally figured it out, something the dealership or mechanic should have figured out immediately. Especially since 3, 4 share a coil. Hello…..Mcfly!
 

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(formerly) 03 H6 OBW , (presently) 06 WRX Sportwagon & 2021 Honda CR-V
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anyone can have a bad day but, according to google maps, Premier has the lowest rating of soob dealers in that area.
 
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