Ok, I just looked this up on one of the resources that I have available to me, and the passages in the intake are what is the MOST common cause of an EGR flow code on those engines with the aluminum intake plenum. Take off the EGR valve, leave the tube alone, clean out the plenum and you'll be good to go. The test for this is to supply vacuum to the EGR valve (hand held vacuum pump, bypass the solenoid, manually energize the solenoid, etc...) and see if the engine stumbles. If it doesn't, you probably need to clean the passages. If it does, then you have either a DPFE sensor problem, or you're not getting vacuum to the EGR valve, due to a broke hose, bad solenoid, bad signal to the solenoid, etc... Hope this helps! If you have a code for the DPFE, then you need to replace that.