IknowHuhA6

That's easy physica... or Physics in layman's terms. Sorry had to quote a little "Big Bang Theory" for those other nerds out there.
Brake Spray applied to where you "think" there is a vacuum leak on a running engine will confirm a leak. Turn the car on and leave it running. Then spray break cleaner from any auto parts store on area you think has vacuum leak. If the car's idle fluctuates... BINGO, you've found your leak.

An engine is a huge air pump. If you introduce a new source of fuel/flammability to the system it will act accordingly and behave as if you are stepping on gas pedal and adding more gas, thereby accelerating engine. Break spray will not ignite on a hot engine but you definitely do not want to introduce it to an open flame or very hot exhaust manifolds/headers.
If no vacuum leak, the brake spray will not make it into system and confirm there's no leak at that spot. Make sure you use narrow straw to more precisely isolate leak. You dont' want a cloud of spray all over the place making it harder to find the exact location of the leak.
Good luck.