Donald Trump's campaign has "a couple of surprises left" in the remaining days before voters head to the ballot box on Nov. 8, former New York Mayor Rudy Giuliani, who has been serving as a surrogate and adviser to the GOP nominee, said Tuesday.

"I think they are surprises, the way we're going to campaign to get our message out there and maybe in a different way," Giuliani told Fox News' "Fox & Friends" program. "You'll see. I think it will be enormously effective. I do think that all of these revelations about Hillary Clinton are finally having an impact."

The news that Virginia Gov. Terry McAuliffe, a longtime ally of Bill and Hillary Clinton, had donated nearly a half-million dollars to the campaign of Dr. Jill McCabe, wife of Federal Bureau of Investigation deputy director Andrew McCabe — the investigator involved in Clinton's email probe — was a "shot to the solar plexus," said Giuliani.

Meanwhile, the former mayor pushed back at talk of Trump's campaign declining, saying that his rallies show a level of enthusiasm that he's never seen before.

"My own rallies, when I won by 18 percent, I didn't have enthusiasm like that," said Giuliani, while insisting that if pollsters didn't use oversampling to account for Democrats, the polls numbers between Trump and Clinton would be even closer.

In addition, the pollsters are using a 2012 model for the 2016 election, which is "totally different," and more Republicans have returned early ballots than have Democrats, said Giuliani, but it's hard to tell how they voted.

"He's probably doing a lot better between independent and Democrat than [2012 nominee Mitt] Romney did," said Giuliani. "He had much more appeal. I can tell. They were blue collar, ordinarily registered Democrats who will vote for the more conservative Republican candidate."