Got some exhaust leaks fixed and reset the ECU (unplugged battery, pressed brake for 15 seconds, sat for 30 minutes, warmed up and drove.) I'm getting a weird boost fluctuation when i execelerate in 3-5 but esp in 5th. It's done this before but usually goes away after a ecu reset... Mods, Uppipe, downpipe, catback, header, intake. Recorded it via cellphone: http://www.youtube.com/watch?v=QcUqCMtD3CE
any engine management? if not i'd just blame the cold, plus your wastegate duties will appear more dilliberate in a longer gear with more load.
the intake could be causing low maf voltage, make your ecu go all kinds of screwy. try the stock air box. see if things level out.
same thing was happening to me awhile back. not sure if this was the case but some of my hoses on my bov were loose and when it hit full boost, I am assuming it'd leak. even though i didn't hear anything. haven't had problems since i pushed them on further. this could have nothing to do with it. just my 2 cents
If the car is a WRX I would bet on a mis adjusted WG actuator arm. Very common with no EM to control it. Alot of people put a couple of turns on the arm to give it a bit more preload. With tuning that can be very powerful, but without it can lead to the issue you are having. That would be my guess...
Definitely, without tuning if that wastegate arm is not exactly right it will throw things off and I have NEVER seen any two that were the exact same from the factory for some reason.
EM and punching the gas at too low of a load. I never understand why people go WOT at under 2500 rpms.
i have a td04 you can steal the waste gate actuator on if you want. let me know you can come get it at fellini's on howell mill rd. see if that helps you out.