Vacuum Pump?
 

After installing headers, I realized that there was a hissing/ticking sound coming from my engine. I thought it was an exhaust leak, so I felt for air coming out of all components with a piece of paper with no luck.
However, I think it may be the vacuum pump and I just did not notice the sound prior because I wasn't actively listening for it?

1) coming from right backside of engine
2) when I press brakes 1 time its okay, but on second it locks up and becomes really firm
3) when I press brakes repeatedly, my STFT rises dramatically to ~ +15. when i stop, it goes back down to within plus or minus 3.
4) My LTFT is at +5% cold start, +7% idle.

I'm not getting any CEL codes...

This is an automatic, so I'm assuming its the vacuum pump?
Thoughts?