its that funny part back of intake manifold
what part clogs first is the mystery of the universe.
EGR
yours, is at:
far rear, all the way down and on the #4 intake runner.
it mounts at the rear of #4 runner.
then a steel tube from it to the top intake plenum and the oriface inside plenum
most likely will be clogged,
so drop tube and poke a piece of bailing wire up in there and clean it out.
just jab away dont be shy. (old romex wire would work or coat hanger)
3 places to clean.