cruise throttle surge

[fixkick]

the vacuum that leaking is coming from the metal line that leads to the intake. when the egr valve is closed the vacuum leaks out of the valve. the exhaust port side is sealed from the intake side of the port. (I haVE NO IDEA WHAT THIS IS.
WE NOW LEARN THAT THE CAT IS MISSING OR GUTTED, AND THAT MEANS THE MOD IS NOW DEAD.  no more 0 to 2 psi exhaust back pressure from hose 13 .
so EGR is  now dead forever, due to that one missing fact not told post 1.  oops

i

here is how MOD works if  BARK hose is dead, (cat missing or gutted, does that every time) there can be no EGR no Modulation possible making EGR main DEAD. and code 51 DTC.