EGR Low 0401 CEL and 4x hubs

[99 Ivan]

OK, no where else to turn for answers and I know (sure the hell hope becasue its driving me crazy) someone here has to know.
1999 4.0 B4000 4X4, 177K.
I had the head gaskets replaced, since I've had the P0401 CEL, before I had the lean code and 401..
Coming off the intake (drivers side in the rear of the intake) there is an elbow with 3 red vacuum lines and one yellow and one red is EGR related. From what I learned tonight (after a few beers and some line chasing), the other two red cross over the rear of the intake to the passenger side of the motor. From there, what I can tell, one of the red lines serves the passenger side 4x hub, the other goes the an insane route back to the drivers side for that 4x hub.
From what I can see, one of the red lines that serves the 4x was pinched in the intake bolt in the rear, the other seemed ok even though they should have been tied together in the flexible holder.
For the love of god, I hope it makes sense, here are my questions if you followed me so far;
1. what size are the red vacuum hoses? 1/8"?
2. could I pinched lines or a broken/cracked or leaking vacuum line for the 4x on either or both sides have any relationship to the P0401 code?

 

[99 Ivan]

I should add, I just replaced the DPFE valve and vacuum check the red, yellow and green EGR vacuum lines.. Redneck checked them btw, blow hard and no leaks. If I unplug the elbow from the intake while its running, it immediately starts to run very rough. if I unplug the EGR valve while its running and put a longer line on it and suck, it almost stalls. Probably not a great idea because its drawing in exhaust but I don't have a vacuum test thing..