I have a 1972 mustang that has been idling rough and at times dies out. When it sits for awhile and I start it up it idles fine when I shut it off and go to start it again it barely idles however its fine when im on the gas. I noticed at the vacuum tree I have three lines one going to the brake booster one going to the canister and one to the vacuum moduler at the transmission when i take that line off it idles fine. Could that be the reason of my rough idle being i have a bad vac moduler?