EGR Problems!
Reply #1 –
how far did he move the plunger? if it was not all the way open, it may not have allowed enough exhaust gas to flow and choke it out. also perhaps part of the passageway it goes through is clogged with carbon deposits. you may have to pull it apart and have a look inside. im kinda leaning toward a blockage though, since you forced it open and nothing happened (noticeably anyway)
not sure about the vacuum. recently i did the same thing, pulled the line off, capped it with my finger, didnt feel it sucking at all. though it was at idle, so there would be no vacuum. nice little slap myself in the head moment right there. but you DID rev it up, so i got nothin for that.