Ok well for the longest time i thought i had a boost leak because i had a hissing noise when i got into the 3k-4k rev range, and thats when the car makes full boost if i have my facts straight. After doing a boost leak test i found nothing, which leaves me confused as to what could be making the noise. The sound is on the drivers side of the engine compartment, Ive run out of places to look. Could it be something to do with the brakes? b/c i think thats where the master cylinder is located. hope this makes sense to you guys.

 

Completely unrelated but the CEL just turned on with 2 fault codes, 17522--Bank 1, sensor 2, internal resistance too high. and 16804 catalyst system, bank 1, efficiency below threshold.

Form what i read it sounds like a o2 sensor going bad but I am not sure.

Any input to either of my problems would be greatly appreciated.

 

I would check ALL of your vacuum lines for the first problem; the vacuum hoses VW/Audi use crack very easily and can be very hard to spot due to the covering on the lines. Your fault codes indicate a bad rear O2 sensor.

 

hmm, my car makes a similar noise. I thought it might just be turbulence in the boost gauge or SMIC. I dont have a leak so Im not worried about it.

 

It's hard to say without hearing it in person. Though I'm not an expert on forced induction cars anyway.

 

okay ill check all the lines but if i have a leak in one of the vacuum lines wouldnt the car be running poor? The only weird thing it does is when you start it up and it runs around 1200rpm at idle for the first minute.

 

Depends on how bad of a leak it is, and a vacuum leak can certainly do what you've said. In fact, that makes me think even more that it's a leak. Worse vacuum leaks can make your engine surge, particularly at idle, and do all sorts of other bad things. They will also make your car slower most of the time.

 

do you have a boost gauge?

 

no boost gauge yet.

 

well then the car should be making full boost before 3k RPMs. if you had a boost gauge and werent getting full boost untill 4k that would be a problem.