EGR issues Options

[brandon702bmx]

I have a 1994 Celica GT and something has been happening of recent that I can't really understand. So I'll begin. I notice every once in a while when I'm driving my car I'll get a significant performance increase when the line running from under the EGR valve gets thrown off the vacuum regulator and I don't understand it... It's like night and day difference. I've had this happen a total of 4 times so far and I know it's happening because I can hear a "throbbing" noise coming from the hose that runs from the EGR to the regulator. What could be the issue with this? I did swap engines and did the vacuum lining myself. Could there be a possibility I did not do the vacuum correct? It runs poorly when I hook it back to the regulator. But it runs wayyyyyy better when it is disconnected and it does it by itself?... I'm lost...