repalced my EGR valve which went out at 23000 miles, what would cause that??

 

hmm, are you sure it was your EGR valve that was bad? Those usually go bad because of a build up of carbon in them. That's the only thing I can thing of, maybe you just had one of those that were poorly built ans slipped though. it happens.

 

Did the diaphragm have a hole in it? Pull a vacuum on the valve and see if it holds it. If the valve won't move when vacuum is applied, then the diaphragm is leaking or the valve stem is seized in the body.