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Old 09-07-2010, 08:19 PM   #1
Scooby Newbie
Member#: 124457
Join Date: Aug 2006
Default engine performance and cats, including funny noises.

OK, ill throw this out and See what happens.
Friday, after about an hour of driving, we started having some issues with our 02 legacy 2.5GT. it was severely down on power, the throttle lag was worse than normal, the check engine light came on (dunno, didn't check it) and we started getting an intermittent noise from the engine bay. it happened regardless of AC on or off, idle or throttle or coast, in gear or not, moving or not. not quite a squeal, not low enough to be a grind. felt the vibrations slightly throughout the car. limped it home, started poking around. could not get it to make the noises again in the shop. so i backed it out, and when i shut it down the noise happened again. about 2 seconds in duration, sounded like in front of the passengers side foot well area.
so i had it towed to the Subaru dealer over in asheboro. they called me today, and stated that is needs new cats (116K), and that was what was causing the throttle response, lack of power, etc. could not get it to make the noise again, but had the theory that it was the exhaust escaping via the EGR system. ( i have never heard of that, and i think that idea is absolute crap. I'm willing to be told different, though)
they wanted to hit me for almost 2000 bucks for the cats.
i found that walker exhaust has them made and sold through rockauto for 260. i have no problem putting the car back on my lift and swapping parts. but I'm wondering if this diagnosis sounds correct given the information i provided, and whether or not the walker parts are worth buying. i do have to pass emissions here in NC next month.
so, let me know what you think.
the history of codes on the car in the past 6 months are:
1. P0420: catalytic converter efficiency below threshold.
2. TPS sensor input voltage low.
I've replaced the rear O2 with a new Bosch piece, readjusted the TPS sensor, cleaned the IAC and MAP sensors, new plugs, wires, filters, ran the valves, and checked for vacuum leaks. none of this has made any of my problems with power, fuel economy, or throttle response any better. matter of fact, its all been getting worse.

anyway, please advise before i spend money and time that i don't have in excess quantities.
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Old 09-07-2010, 09:55 PM   #2
Scooby Newbie
Member#: 161322
Join Date: Oct 2007
Chapter/Region: Tri-State
Location: Galeton, PA
06 2.5i
Regal Blue


buy a used rs cat section and be done with it. Clogged cat will do all you said, except for the noise. the EGR is exhaust gas recirculation, AKA returns exhaust back into intake for reduced emissions.
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Old 09-07-2010, 11:20 PM   #3
Scooby Specialist
Member#: 80465
Join Date: Jan 2005
Chapter/Region: RMIC
Location: Bailey, CO
2001 2.5RS
Black Diamond Pearl


It kinda makes sense. The cat is clogged, so exhaust gas has to go somewhere. Right into the EGR system. Get a used cat section.

You could try to cut a hole just before the cat section as a last ditch effort/troubleshooting step before replacing.
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Old 09-07-2010, 11:23 PM   #4
Scooby Specialist
Member#: 231058
Join Date: Nov 2009
Chapter/Region: TXIC
Location: San Angelo, TX
2015 F-150


$2000?!?! That's outrageous. You could buy a full exhaust and have it professionally installed for half that. I would call the dealership back and ask them why they think that their service is so special when you could have any reputable exhaust shop install a new cat for 1/10th of the price
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Old 09-08-2010, 07:43 AM   #5
Scooby Newbie
Member#: 124457
Join Date: Aug 2006

so wht im hearing said is that it is not far fetched given the symptoms that the cats went bad. ok, no porblem. ill put new ones on it. with this many confirmations, im willing to try. will the aftermarket walkers work well and pass the OBD check, or willit be like my old dakota where it never would get the CEL to go off?

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Old 09-08-2010, 03:06 PM   #6
Scooby Newbie
Member#: 254417
Join Date: Aug 2010
Chapter/Region: MWSOC
09 Impreza


If you get a cel just get the o2 spacer and you will be fine. Before I would run to buy new cats i would drill some holes in the old one to see if it fixes the problem, if so get your new cats.
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