Good sign that your EGR is opening too early is a rough inconsistant idle. After installing the Street RV head I had such strong manifold vaccum that my original EGR was being pulled open at 850 RPMs. I messed with damn near every sensor and adjustment under the hood trying to figure out the idle problem. Then out of the blue after applying vaccum to the EGR valve directly and it passing...it hit me. Ya know...my idle seems like a mild case of what happens when testing these things. Pulled my EGR and sure enough, the thing wasnt closing all the way thus allowing exhaust gases to intermixate ( <img src="/forums/images/graemlins/notooth.gif" alt="" /> ) at idle when the ECU wasnt compensating for it. Just a thought you may want to check. After replacing EGR with a spare things was fine. Of course the I have Zero vaccum going to the new EGR now...and it opens up on its own as RPMS increase...NO I aint kidding!
~Darin <img src="/forums/images/graemlins/baby.gif" alt="" />