clean egr pathway

I replaced my egr valve and still throwing a code for air flow. I was told I might need to clean the airway where it enters by the plenum. What is the right way to do this?

2004 3.4 base impala

Thanks!

Ok, during a decel, the PCM tests the EGR, by commanding it to "slightly" open.....it then looks for a corresponding change in the MAP sensor...if it does not see this, a P0401 is set.....

so if there is blockage to the EGR, or after the EGR, this could be the problem.....

There was an old TSB, on much older cars for this problem......it was that the passageway in the upper plenum, could have some "flashing" present in the passageway, and over time, crud builds up, and then when the PCM does the test, it can't detect the slight opening of the EGR during a decel.....what they wanted us to do was remove the upper plenum, do an acid bath, and clean out that passage way.....some guys would just remove the EGR, spray carb cleaner or Brake Klean in the passage way, run a mechanic's wire through there, open the throttle plate, stick a rag where the opening was, and then blow throw the opening with an air gun....the rag would catch any "flashing"/dirt that might have come loose....

Ok, during a decel, the PCM tests the EGR, by commanding it to "slightly" open.....it then looks for a corresponding change in the MAP sensor...if it does not see this, a P0401 is set.....

so if there is blockage to the EGR, or after the EGR, this could be the problem.....

There was an old TSB, on much older cars for this problem......it was that the passageway in the upper plenum, could have some "flashing" present in the passageway, and over time, crud builds up, and then when the PCM does the test, it can't detect the slight opening of the EGR during a decel.....what they wanted us to do was remove the upper plenum, do an acid bath, and clean out that passage way.....some guys would just remove the EGR, spray carb cleaner or Brake Klean in the passage way, run a mechanic's wire through there, open the throttle plate, stick a rag where the opening was, and then blow throw the opening with an air gun....the rag would catch any "flashing"/dirt that might have come loose....