I recently had my engine rebuilt. I noticed a vacum leak sound coming from the right of the intake (Standing inf front of the car looking at the rear). I could not find the leak anywere. The other day I was dusting off the MARO and noticed the vacum leak sound really strong coming from under the center of the hood, around the rear of the engine. The vacum that goes to the EGR (?) is connected with no flaws. What could this be? This causes hard starts when the car has cooled. Please help.

 

Any Ideas what this might be?

 

The line going to the Fuel pressure regulator?
PCV valve?

 

Were do I find the fuel pressure regulator? Is there a diagram (pictures) out there that shows each vacum line and were its supposed to go? I appreciate any help, I'm stuck!