He's baaaccccckkkkkk....Ok team, got another issue, I can't find the solution....yet.

As I said a bit ago...failed cal. smog...too high NOx reading...everything else is fine, great actually...plugs are white and running lean no matter what I have done...timing is spot on, truck starts instantly, idles a tad rough though...I have checked the vacuum lines and everything appears fine, I pulled off the intake manifold and scrubbed out the egr passages and also through the cylinder head, my cleaning rod came out of the #4 cyl exhaust port...here's one thing I can't figure out...I removed the egr valve, put a vacuum line and sucked on the line, egr held vacuum, both small ports on the top of the egr held vacuum, when I run the truck at idle no response from the egr which is normal, when I rev the motor, still no response from the egr...It should respond by opening, when I depress the egr manually at idle...nothing, the motor continues to idle normally, it should stumble and/or stall right?...I have this feeling this is something I'm just overlooking or considering...give me a heads up.