Ko was left frustrated with the her putter after finishing her second round with a three-putt bogey and missing several birdie chances late in the round.
With the tournament still a bit behind after a first-round fog delay on Thursday morning, play was halted by darkness with a handful of players yet to finish.
She hit 10 fairways and 10 greens and had a steady 28 putts but in a 10 hole stretch in the middle of her round she dropped six shots.
Lexi Thompson was among five players one shot behind.
Seminole’s Brittany Lincicome was 2 over through 11 holes of the third round. Jang made a late birdie to take the lead en route to a final-round 72. That gave her 69. I just hit all of my, apart from the third one, a little too hard. “I finished so good”. “Not like we can play in really unsafe conditions”, she added.
Chun, who was set to continue her round at the 10th hole yesterday, bounced back from two early bogeys with three birdies in her last five holes of the day.
Ko played with Morgan Pressel, who was 3 under, and Paula Creamer, who was even. They could tell storm clouds approaching and Creamer jokingly said that play would be stopped right before they finished.
The tournament is still hopeful of ending on Saturday.
Ko, 18, was playing her first event of the season, having skipped last week’s Bahamas opener to better prepare for upcoming title defenses in New Zealand and Australia. First-round co-leaders Shane Lawry (70) and Hideki Matsuyama (70) were 7 under. She summoned a rules official to discuss whether her ball moved on the sixth green. Els was tied with Trevor Fisher (68) and Danny Willett (65). She was at 4-under 140. Tom Lehman and Billy Andrade had 67s. He had three birdies in his last three holes to finish three above the cut line.