egr problem.
How I fix mine.
First took off EGR valve set it aside. Start engine and see if any vaccuum at small hole. if engine runs as usial (no rpm change with EGR removed)- there is pipe inside plenum clogged for good.
Shut engine off.
disconnect air intake hose.
get throttle fully open and look inside the plenum (flexlight can be usefull)
will see pipe on the bottom - with tiny hole ( usially sludge on it a LOT)
getting air blower (shop air high pressure) and blow air through that pipe
CAREFULL!! use safety glasses
Lots of debris flying out from egr vac hole on the back-hood reflecting that stuff towards you
put air intake hose back
start the engine - note how engine runs(or not) with egr off.
turn engine off. put egr back on
clear codes, wash, shampoo engine.
Happy wheeling))