The 28-year-old Northern Irishman, a former world number one now ranked fourth, is rated a 20-1 shot by bookmakers to repeat his 2014 Open victory at Royal Birkdale this week.
"It hasn't been the year that I had planned, but these things sort of crop up out of nowhere and they challenge us," McIlroy, who suffered a rib injury in January, told a news conference on Wednesday.
"Obviously, it's been hard to get any sort of momentum with an injury and not being able to practise as much as you'd like," he added.
"But I'm in good spirits. I feel like it's all coming together. I'm just waiting for that round or that moment or that week where it sort of clicks and I'll be off and running."
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McIlroy's last major title came at the 2014 U.S. PGA Championship a few weeks after he won the British Open at Hoylake and he looked set to dominate the sport.
"Having that success, you only want to do that more. You want to do it again and again and again," he said.
"So I definitely haven't lost the hunger that I've always had," McIlroy added.
"A second Open Championship isn't going to change my life, but I'm still as ambitious now as I was starting off my career, if not more so now because I know what I've achieved and I know what I can achieve."
McIlroy played his first British Open as an 18-year-old at Carnoustie 10 years ago, and he is well satisfied by his achievements in golf.
"If someone told me 10 years ago at Carnoustie 'You're going to be a four-times major winner and you won The Open, you're one leg away from the career grand slam and you've played on three winning Ryder Cup teams', I would have said 'I'll take that, that's pretty good'."
McIlroy believes he is playing well enough to tame the notoriously tricky Birkdale links course and beat the favourites, world number one Dustin Johnson and his fellow American Jordan Spieth.
"It's just about staying as positive as I possibly can," he said. "Hopefully, the start of another crest of a wave happens this week. My game is all there. It's just a matter of putting it all together."
(Editing by Hugh Lawson)
