I hate to say it, but check a couple more times.
this sounds like it could be a ripped injector wire or an unplugged/broken/dirty MAF sensor to me. A little vacuum leak shouldn't cause that bad of an idle.
Who's this "everyone" you talked to?
good suggestion.
Your gap is fine, don't worry about it.
A good thing to do at this point is to pull every plug and see which one is wet with fuel. That will at least give you a good spot to start.