Sounds like the dv. I swapped mine out last month with the latest version, and I noticed right away that it didn't sound the same under boost.
Had my 75k service done yesterday and while it was in they changed out either a PCV or diverter valve (I'm not sure which) at the same time.
When I drove it off, I thought that it sounded a little different under load/boost, but shrugged it off. -When I started this morning to drive to work, it sounds VERY different under boost... as if someone is blowing through a straw. -Hard to describe.
I'm still seeing normal boost on my boost gauge (peaking at about 15psi, typically holding in the 10-12psi range, but I've not tested that specifically) so I don't suspect a boost leak right at the moment.
I put a call in to my service writer, but I'm wondering if anyone else has experienced a similar thing, or if I'm concerned for no reason.
This is not related to excess-pressure blow-off or anything like that (I'm all stock in that dept) because it happens under sustained engine load, not on lift-off particularly.
Also check around for various parts not connected or loose fasteners.
Also, the top of the new valve assembly seems to have a hole on it... not sure what that's all about...
But something is wrong. VERY wrong.
My gas mileage is down. SIGNIFICANTLY down. -Remember all those 400+ miles-per-tank runs that I've done? -Well this time I'm struggling to get anywhere near that. -Just did a long weekend's driving (about 6 hours each day) and had to fill up twice at about 250 miles.. I wasn't empty, but driving through wilderness, and my gas mileage AND motor torque is all messed up, and I didn't want to run out in the middle of nowhere.
Going to scan with VAG-COM for faults (no CEL showing, but I'll check anyway). -This car is definitely NOT at 100% top health.
I hope that the 600 miles I just put on it hasn't meant anything nasty in terms of intake or plug fouling, if the mixture is off or anything like that...
Hang on, I'll put a couple of snaps up.
Okay, so where you have an unattached hose like this:
...I have an unoccupied hose barb like this:
...you can *barely* see it just next to the injector harness loom.
...and here's the shot of the opening at the top of the valve... not sure if this is how it's supposed to be or what?
In addition, since there's a chance that this line varies pressure, and is likely under vacuum at various times, there's a decent chance that dirt, grit and sand has had ample opportunity to get in. -Currently the engine also hesitates very slightly at times when it didn't before. -Something's off. Fuel mixture is possible, if not likely...
So I'm taking it in to the dealership tomorrow. (my assigned service writer has a day off today) so that THEY can see what the problem is. -Then we're going to sit down and have a bit of a talk.
But MisterJJ, thanks for the photo and for giving me a solid suspect. -While I've got nothing against my dealership, this is not the first time I've had an issue like this, so I'll initiate a discussion centering on how they can restore my faith in a couple of matters. I'll say no more publicly for now; they can definitely 'save' this, but it's up to them. -I need to feel reassured that silly little oversights don't become bigger problems.
I wanted to listen around while 'blipping' the throttle, but damn these drive-by-wire cars, there's no throttle cable under the hood! -One day if I find myself faced with this often enough, I'm going to make a long extension cable and wire it on to my old throttle pedal (which I took out when I put the GLI pedals in) and maybe mount it to a non-slip rubber base, so that I can blip the throttle while I'm under the hood... yeah... -necessity being the mother of invention and all that.