The Swede leads Spain’s Julia Lopez Ramirez, who climbed to second in the leaderboard after producing a round-of-the-day 68.
The pair will be last out to start their final round, at 19:10 BST on Sunday.
Japanese trio Mao Saigo, Hinako Shibuno and Rio Takeda are all tied on five under in third place.
Successive bogeys hampered overnight leader Saigo’s pursuit of a second consecutive major title to finish with a three-over 75, while world number one Nelly Korda remains in contention and trails Stark by three after making three birdies in her final five holes.
“The first thing is that I would like to rest well and then tomorrow refreshed,” Saigo, who won this season’s Chevron Championship, said.
“I would like to start from zero. That result was not that good, but I don’t think that I have to change anything. I just want to focus on my play.”
