Been having this issue for a while now, but am trying to address it prior to getting out of front end service mode. Basically a constant hissing occurs and sounds like it is under the intercooler around cylinder 2 and 3. I pulled the IC, and pulled both of the small vacuum hoses and 'pressure tested' by blowing through them and covering up the other end. Both seemed solid, but I replaced one due to the rubber perishing pretty hardcore (did not replace the fuel pressure regulator vacuum hose).
I also noticed injector 3 looked pretty gunky around it.

Injector 3 pretty gunked up. Rest look clean and dry.

I pulled the PCV and tested it as well and it seemed fine. I felt around the other lines around there, the white/grey one that goes to the SC and the one that heads to the throttle body and did not feel anything, but this was obviously without the car running.
After replacing the other short vacuum line, I still have this leak. Any ideas? I assume if it were the fuel injector leaking it would smell of gas, which this does not. There are also no codes associated with this leak either.

On a side note, it appears that the TB was replaced at some point, and the PCV rubber hose was poorly replaced and is rotting as well, but again, this is not where the leak sounds like it was coming from. I mention this due to perhaps the throttlebody to SC boot might be a cause? Apparently these are a huge pain to put on? (havent touched it yet)
Another side note, the previous owner may have been a homeless squirrel. Wish I took a video of when I replaced the cabin air filter, like 2 pounds of nuts came raining out...