Vacuum hiss heard from driver's side dash area

[Ahlem]

Looking for possible culprits making a vacuum hiss heard while sitting in the driver's seat. It seems to be coming from under the dash. Are there any vacuum switches in these, similar to a Chevy Astro. It may be a power brake booster but nothing seems out of the ordinary on a simple visual inspection.

 

[Ahlem]

Upon further inspection, it appears we screwed up the seals on the fuel injector housings when we were servicing some things in that neighborhood.
Can anyone suggest a link to a solution? I'll be searching the FSM next.