McIlroy is one of the longest hitters on the PGA Tour but the four-times major champion decided to change his driver at Riviera after watching Tiger Woods (47), who is still having issues with his ankle, outhit him off the tee.
The Northern Irishman finished in a share of 29th at Riviera and last week was joint runner-up at Bay Hill but he struggled off the tee at TPC Sawgrass en route to a four-over-par 76.
"Look, I wish I could use my driver from last year, but I can't just because of - you use a driver for so long, and it starts to get a little too - basically it just wouldn't pass the test," McIlroy told reporters.
"These driver heads are so finicky, it's hard to get one exactly the same. I'm obviously trying my best, trying to get something that's as close to what I had last year.
"Yeah, just struggled a little bit off the tee the last couple weeks."
At Riviera, McIlroy ditched a first-generation TaylorMade Stealth Plus that had been a mainstay in his bag since the start of the 2022 season in favour of a new Stealth 2 Plus while also changing the loft setting.
The Northern Irishman was routinely hitting out of the rough on the tricky TPC Sawgrass layout after errant tee shots and was never able to find any rhythm.
When asked if he was working on trying to find a new driver, McIlroy admitted he need not put all the blame on the club.
"This one is as close as it's been," said McIlroy. "Yeah, there's obviously a part of it that's the user, as well. It's quite a lot of user error in there, as well."
