See pic, watch for this. Mine fell off the nipple on the intake and makes for big leak. My fix was this clamp from my spare parts box. Be sure the three large hoses that plug in the accordion are in place, one goes to the black box on the firewall, and the other two go to their respective side valve covers. Those ells needs to be in good shape, they break, crack, leak. This is not vacuum but fresh "metered" air.
As noted in the other post, the tranny vent is not rocket science. It is a vent. It keeps dirt and water out. It is easy to hit the rubber cap and plug the vent and it makes a fluid mess. If your cap is missing the hose fix is fine. I prefer clean caps put on according to them being wobbly loose like they were designed. When you start the engine, the fluid level drops and some air must go inside. When you shut the engine off the fluid level rises and that air must escape. If the vent is plugged, it pushes the dipstick up and some fluid pushes out the top of the tube. Been there.
Thank you both for your help! I was afraid that it might be a vent for the transmission but was really hoping that it wasn't so it could be the source of the vacuum leak. No such luck! LoL
All the lines on the intake are connected well, no rips or cracks on the intake tube between the MAFS and the throttle body either.
I'm going to pull the upper intake manifold back off this weekend (if nothing else comes up between now and then) to see what the plug from #2 looks like and check everything back there. If I can't figure it out I will start a new topic on the subject. The fact that it is only cylinder 2 and only when cold is driving me crazy.