Never noticed any vacume leaks with it, but in the future i will check it out. maybe....
never thought of the EGR valve. i just thought it was odd why it would idle the way it would when you pull up to a light. kinda dangerous to if you ask me........

Again thank you for your help.........

 

WOW.I have the same problem.I just changed the idle air control valve and it sometimes idles at about 1500 rpms when at stop.It is kind of scary.96 blazer 4x4