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Sept. 7, 2010 9:03 p.m. Dusterbd13 New Reader

OK, ill throw this out and See what happens.

Friday, after about an hour of driving, we started having some issues with our 02 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.

michael
Sept. 7, 2010 9:11 p.m. Toyman01 SuperDork

About half way through your post I was guessing cats. I just had to replace them on one of my vans. $800.00 If I had to guess the front cat collapsed into the rear one and stopped up the whole mess.
Sept. 7, 2010 9:24 p.m. Wonkothesane Reader

It should be fairly easy to test, most of the time when a cat bites it, it'll glow nice and red if you flog it a bit. This is easier done at night. Take it for a spin, then get it back home and pull up on the ramps and stick your head under there. Are your kitties glowing red? They're stuffed.

You can test this if you're handy (and you have patient neighbors), pull the cats off, take it for a rip up the road. If your power is back, you're good.
Sept. 7, 2010 9:56 p.m. fornetti14 Reader

Dad just had his cats replaced on an '03 Forester (140k). I think there was a recall on them. No way I'd pay $2k at the stealership. Buy the Rockauto ones and sell your old cats for scrap. There's a guy that buys them all the time on NASIOC and I'll bet you get close to $80-$90 for them.
Sept. 8, 2010 6:01 a.m. ddavidv SuperDork

If you had just said P0420 code (cat converter) I'd have laughed and said ignore it. Subarus have a ultra-sensitive dual O2 sensor system that triggers that light if you burp while driving. But, the other symptoms would indicate a sudden (which is a bit odd) cat failure. They have been known to have cat failures from time to time. Absolutely buy the aftermarket ones. If you do this, it runs fine but still triggers P0420 I can give you a simple fix to turn it off forever.
Sept. 8, 2010 6:39 a.m. Dusterbd13 New Reader

well, ive had a lack of power (not as severe) and poor throttle response for about the last 6 mos-year, that ive been trying to figure out. it just got suddenly worse.

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?

michael
Sept. 8, 2010 6:40 a.m. 44Dwarf HalfDork

Well i had same problem with the 98 forester last year. 4 days after cleaning the MAF and throttle body with the "proper cleaner". (a well know 3 letter brand) started poping the 420 codes too. Ended up towing to a shop while on vacation in maine and paid $200 for a MAF. Still pops 420's twice a month even replaced both O2's no luck hopefully we get a sticker as it's due next month. Last oil change i almost cleaned the MAF when i did the air filter but stoped in my tracks...not making that mistake again.

44
Sept. 8, 2010 7:56 a.m. Woody SuperDork

Wonkothesane wrote:

It should be fairly easy to test, most of the time when a cat bites it, it'll glow nice and red if you flog it a bit. This is easier done at night. Take it for a spin, then get it back home and pull up on the ramps and stick your head under there. Are your kitties glowing red? They're stuffed.

I'm not sure exactly where they sit on these cars, but just check to see if the undercoating in the area of the cat has melted. That's a good indicator that it's been doing the red thing.