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Discussion Starter #1
ok i bought a 2008 STi about a month ago with 34k on it .

it already had full turboback magnaflow exhaust (w/cats) and FMIC w/ tial BOV,
no problems.. driven for about 1 month roughly 800 miles and havent really beaten on it like i would usually cause its new to me and i love it.. launched once and maybe made 1 -2 real full hard core passes on the car for $hits and giggles . couple of days ago got CEL (while driving down the highway normally in I mode)and its not in any type of LIMP mode, got the codes checked and got (2) P0171 codes (system to lean bank 1 ) and a P0420 (catalyst Efficiency below threshold bank 1)

now i do not know if the car was flashed or not ? ( how do i tell if i have no clue about ecu flashing?)
but is this somthing the dealer will be able to fix? or do i NEED to have a ecu flash for my car for this to stop happeneing?

please help.. please no bashing or what not..
 

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3 Main things

1. Find a local shop to have it professionally tuned.
2. Replace your Blow Off Valve with a Recirculating Bypass Valve
3. Check for boost leaks by checking all the couplers on the Front Mount Setup.

If you need a price on a bypass valve, let me know.
 

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Discussion Starter #3
i need a price for a bypass valve apparently LOL and why is this BPV a big deal why is a BOV bad?
 

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I agree with Kronos and all his suggestions, but I think your problem is the aftermarket cats. Do you have the stock exhaust?
 

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i need a price for a bypass valve apparently LOL and why is this BPV a big deal why is a BOV bad?
Bov does nothing good for any subaru and they are notorious for throwing codes. The BPV vents back into the system instead of venting to atmosphere. The car was designed with a BPV for a reason.
 

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i need a price for a bypass valve apparently LOL and why is this BPV a big deal why is a BOV bad?
You have a vehicle that meters air on a Mass Air Flow sensor and from factory its designed to recirculate the air back there when releasing off the throttle and not direct it to the atmosphere...aftermarket Blow Off Valves tend to leak air during normal driving, not seal properly, cause it to open too early or close too late causing your driveability to go all over the place. I'm not saying thats the reason 100% you're having codes come up but it could be now or in the future. You could be sacrificing power and MPG. Blow Off Valves are great if all you do is go full throttle but you don't have a Race Car. If it was another vehicle that was MAP based, it wouldn't be much of a big deal.
 

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I'd bet the cats are flowing too much and hence the code. The seller could have cleared the code right before you took the car home and now its back. I could be wrong, just going by what I have witnessed in my years with Subaru.
 

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Discussion Starter #9
down pipe
after down pipe
after cat? secondary cat?
 

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Discussion Starter #11
I'd bet the cats are flowing too much and hence the code. The seller could have cleared the code right before you took the car home and now its back. I could be wrong, just going by what I have witnessed in my years with Subaru.
but why wouldnt it do it right away? ive had oit for a month and when the codes popped up i have been driving normally
 

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Wow... there are a lot of places that this could be going wrong. Is there a stock anything in there?

My opinion...
Your "lean bank" code is your air intake.

Your "cat" code is your lack of stock cats.

Both lead me to believe the car needs a tune. If the previous owner tuned it with an accessport - he probably pulled the tune so he could sell the AP on the side. If the owner tuned some other way - I am not sure why they would remove it.
 

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Discussion Starter #17
Wow... there are a lot of places that this could be going wrong. Is there a stock anything in there?

My opinion...
Your "lean bank" code is your air intake.

Your "cat" code is your lack of stock cats.

Both lead me to believe the car needs a tune. If the previous owner tuned it with an accessport - he probably pulled the tune so he could sell the AP on the side. If the owner tuned some other way - I am not sure why they would remove it.
why would you say cause my intake?
 

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Discussion Starter #18
my friend has a COBB AP can i use that or do i need my own?
 

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Discussion Starter #20
You have to have your own. When used it gets married to the computer. It wouldnt work without your friend no longer using it. It would also need to be the right model.
gotcha, and question why wouldnt the light come on right away why did it take a month? only thing i did to the car was the short ram..? could that be the problem..? if the car was flashed for a CAI and i took it off?
 
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