Hey all! new sti owner and first time posting.

first here are the mods related to the engine that may be related to this problem.

-HKS SSQV (was on there.. now stock)
-APS Turbo back exhaust system
-stock ecu programing

Anyhow, I bought a 2004 sti and it had a few thing on it that I did not care for... one of which was an HKS SSQV and the noise it made. So I took it off and put the stock unit back on. Anyhow, I was accelerating hard onto the freeway and at 5k rpm I got a single abrubt buck/hesitation and the check engine light came on and the cruise light flashed on and off.

I pulled off to the side right away the engine was idling smooth... no problems seemed apparent. So, I limped it over to autozone and had them plug in the computer and a wastegate malfunction code popped up "dont remember the exact number" Anyhow... had the guy clear it out and I have not had any problems for a couple days now running the stock unit.

So... what happened? is there anything I should have checked out? Any info would be greatly appreciated as I am uber hungry for info and to understand my new toy :)

Thanks!

overboost.

or.. over boozed :P

why would it overboost with a stock setup? Am I correct to assume that the stock ECU got use to the HKS bov and then spazzed when I put the stock unit back on? Would this happen again now that the code was cleared?
thanks again for sharing your knowledge.

First of all, you need to get some engine management (EM). Accessport (by cobb) or something else, but you are not getting the best out of your setup. You would be what most people refer to as stage 2.

EM will also help to bandaid your overboost (boost creep as some refer to it as).

search for "boost creep" caused by your turbo back

yeah, it's boost creep caused by the downpipe, there are several options on how to fix it.

Great stuff, thanks for your patience on this stuff. I will call up Cobb today and see what can be done.

Any other info advice anybody has... I am all ears.

Pretty much what everyone else said. Boost creep/overboost is your problem. Porting your wastegate has been said to cure it.

Sounds like bootcreep you should really run access port stage 2 for engine management this should fix your problem.

+ for EM w/TBE!