EGR Valve blown?

[MN-Engineer]

I'm having trouble with 'chuggle' and power loss on my '84 Suburban at low RPM with light throttle. It's most noticeable in 30-45 MPH traffic. Suspecting an EGR problem, I pulled the EGR valve off , and tried to blow air through the vacuum line nipple expecting that the bladder would eventually create back pressure. It didn't. I also tried to suck air out, creating vacuum, but got the same result. It doesn't seem to be sealed. Is this normal, or is my EGR valve bladder ruptured?

[freebirthfreddy]

The EGR is a spring loaded rod pushing down on a hole in the intake manifold, the intake manifold has some exaust redirected thru it and when the vacum from the carb or (*insert fuel system here*) pulls up on that rod, the rod unseats and the passage way is opened for some "dead" air to flow into the intake side of the manifold, to the cylinders.

If an egr valve is not opening, the engine will not get the proper level of air to fuel for smog reasons, and the cylinder will run a little hotter as well.

i assume you meant when you blew on the nipple you meant on the egr side of the line. so when the car is at an idle, discannect the egr: the idle should rise 2-300 rpm push up on the rubber diaphragm: the car should stall, as this lets a large flow of "dead" air to the intake side.

if that test show nothing, it could be plugged
I hope all this is right, someone back me up on this, or: it';s all in the Chilton

[GMMerlin]

A good why to see if your chuggle is caused by the EGR is to disconnect the vacum line and drive the vehicle in the rpm range you would feel the problem.
Sometimes you can see the valve raise up and the engine stumble by simply raising the rpms with the truck in park.
The stumble is because of the EGR valve rising too much.