After warm up and normal driving my car will frequently idle rough 400rpm as if there is a vacum leak downstream of throttle plate. Then sometimes it will go back to normal idleing. VSV checked out ok, no codes. According to TSRM my 90 GTE is showing signs of a sticking EGR valve. Looks like a PITA to remove. Anyone have experience with this, any tips or tricks before I attempt to remove.