Vacuum leak v6 2008 mustang

capping all inlet vacuum ports on the upper intake manifold except the red one fuel regulator disables 3 things but the engine will run just fine #1 the egr #2 ac vents switch #3 evap or vapor control unit ,if you have missing vacuum tubes some of those can cause a serious vacuum leak if ports aren't capped off ,next thing to look at are air cleaner tubes they must not have any holes in them inspect carefully next pcv valve get a new one . after vacuum problem solved get your tps sensor calibrated with rpm setting .finally check spark plugs and wires

those mustangs a famous for leaking past the air cleaner that round thing after the air filter .its a black foam gasket that falls apart and wont seal causing the map sensor to read incorrect message from pcm

These answers do not help. Location of the hoses ( Ford hides manuals - I had to buy a Chiltons, the information is not on the hood or in the users manual) and connection points, or point to where they can be found. My car is a 2008 V6, 4.0L, automatic. The idle runs about 700 (gauge) and will sporadically drop to 550 for 1 sec and go back up to 700, usually at a stop, in gear. The problem seems to come and go.