Originally Posted by Decipher
This is the way I took it, too. By all accounts, it sounds like you now have a stock tune on it. If Subaru says you do, then you do. They would know by the codes. The other lack of answers are unacceptable from various shops. I hope you didn't pay them for this crap.
As for the rattle, do the simple thing first and check that up pipe as described. It's simple and may be a quick fix. Unfortunately, with the odd hesitation you're getting, I'm fearful it's something much bigger and more expensive.
It sounds like you have a headache on your hands. Even if the rattle is the up pipe, the previous owner handed you a car with an improper tune. He was probably running an accessport he wanted to sell, so likely unmarried it and resold it. That, or he was running his setup with no tune for the mods at all. Either way, be prepared to spend some money or ditch the car. It certainly sounds like you should have got some more info prior to your purchase. Sorry man.
Unfortunately you can't tell if the tune is stock just by codes. The OEM rom isn't locked, using ECUflash and Romraider you can pull the stock map and make changes all you want and pop it back on there and the dealer will never know because there's no flashlog data or change data in our ECU's. You'd have to have a stock map and compare the tables to the map pulled from your car with your eyeballs.
You can find your specific stock MAP here http://www.romraider.com/forum/viewt...hp?f=35&t=7591
If you get a tatrix cable and download ECU flash you can simply compare the stock rom to what's on your ecu and it will tell you if it's the same or not. You'd want to try all 3 variatons of the 04 USDM STI rom first before drawing any conclusions. If none of them match you can open them up and compare directly.
I don't even think the dealers typically have access to making changes to the ECU, they only have tools to re-flash it with the files they get from the factory unless one of the guys there happens to have downloaded all the Romraider stuff to one of the computers there.
To the OP: it sounds like you have some tuning issues causing the engine to bog like crazy. When you mod the intake and/or injectors you have to take a long time getting the fueling dialed back in because the ECU has to be re-calibrated with the appropriate mass air flow and fueling relationships for the new parts.
Severe bogging and hesistation at partial throttle and low rpm sounds exactly like a closed loop fueling problem.
Explain the rattling sound more. Is it a pronounced knock that increases with the speed of the engine or is it a harsh metal on metal random vibration noise?
I have the vibration noise, it's somewhat common when you have an aftermarket clutch and a lightweight flywheel, when the engine bogs down by giving it too much gas at low rpm, the lighter flywheel will not keep the engine running smoothly forward and crap begins to sound way wrong.
If it's a knock knock knock knock then you're screwed.