Hello XXXXXXXX,
This is not a real bad job & if you are mechanically inclined you can do it.You can clean this passage without pulling the plenum.Pull the EGR off & take note to the port that goes toward the throttle body.This is where the EGR & the intake connect.You can either open the throttle full & lock down or remove throttle body for access to the other end of the EGR port(this is where most of your restriction will be).Use some carb spray & a flexible shaft(old speedo cable works good),spray into hole at EGR & work the cable thru the orifice until you get thru to the intake.Clean out all carbon build up & wipe out as much as possible with shop towel.
Master Automotive Technician
ASE A1-A8 & L1 Master GM Tech 40 years experience