I've got a stock '06 STi, and I've been having some problems with it lately. Yeah, already. After some spirited back country driving, the turbo seemed REALLY noisy. At around 3k, even with light throttle applied, there was a ton of noise (vacuum cleaner, not metal-on-metal), that sounded like it usually did after 6k. I also noticed it seemed very laggy. Where before if I went WOT at 3k, it would take off like a rocket, now it pulls much slower and the turbo seems laggier.

I drove the car to work and induced a minimal travel-high G shock to both the wastegate and the BOV. With the turbo so loud, I couldn't hear whether or not it was opening, and decided it really couldn't hurt. The car seemed to run ok, until last night when I had to dump it down to 4th gear to pass some crazy jackass on 101. I've made a couple of 5500-6000 shifts between fixing the car and then with no problems. Now I'm getting the same issue... the turbo is louder than normal above 3k, and the car seems doggy.

If the wastegate was stuck open, it'd be laggy, but I don't think it'd sound like it was fully spooled. If it was stuck closed, I'm sure I would have overboosted by now and gotten a CEL. I would think if the BOV was stuck open, that it wouldn't be laggy as the air would just recirc back into the intake system, and the turbo wouldn't be trying any harder to spool. I'm probably missing a big smoking gun somewhere, so I thought I'd throw it out and see if anyone has any ideas on it.

Being that the car is under warranty, I could take it in, but I have a serious fear of mechanics. In the 6 years I owned my Integra, it spent 3 years not running because of bad mechanics and bad shops who screwed the car up and left me trying to get money from them in court (which I never could). I'd like to try to fix it myself first before I give in. Also, where would I be able to get a factory service manual? I know they're usually twice as expensive if you buy them through the dealership, rather than from the publisher.

 

Take it back to the dealer immediatly! If the wastegate is stuck you are overboosting each time you go WOT. I wouldn't be suprised if it already blew rings on pistons 2 and maybe 1. I am suprised you arn't seeing a fuel cut. Regardless of what I think, get it back to the dealer = you are under warentee.