I would pick up some vacuum hose from the parts store and replace the EGR line. Then do a visual inspection of everything you can see.
I had vacuum woes on my SD and found that this helped me isolate the different circuits:
Those little black "spider" deals get old and leaky and they don't improve after manipulating them during troubleshooting.
Good luck! Since everything was working before I'm sure you'll find it's something simple!