Bogs when pushing clutch in.

My 87 TC bogs downs when pushing the clutch in and coming to a stop. Usually happens when going from a steady cruise of 2000 rpm or so to idle and does not happen every time. A little back ground, the car has a brand new motorcraft IAC valve, all intake gaskets have been replaced, throttle position sensor is new and voltage is set properly, vacuum lines and pcv valve are all new as well. Im running a gillis valve and stingers front mount with a dual piston BOV. I am assuming it is a vacuum issue of some sort and I am curious if anyone has a similar issue. The car starts up and idles no problem cold or hot.

Have you disabled the BOV to see if the issue goes away with the BOV disabled?

Check for vacuum leaks.

My 35 year old EGR valve has decided to finally give up. I tried moving it with a screwdriver and it sticks open.