"I didn't hit as many fairways and I got some really bad lies in the rough", said McIlroy, who followed a birdie at the sixth with bogeys at the eighth and 12th before picking up birdies from close range at the 13th and 16th.
Woods gave back two shots on his last two holes to shoot an even-par 70, and sits at 8-under after 36 holes.
Northern Ireland's McIlroy briefly threatened to dislodge Woods before equalling the American's score. Woods closed with back-to-back bogeys, missing a six-foot par on 18, in shooting 70 and dropping to a share of 12th. "I mean, Tony obviously is the guy right now".
Tiger Woods failed to take advantage of the great start he got off to in the first round of the BMW Championship, unable to break par on Friday - the only player in the top 12 to not shoot in the 60s.
Woods made four birdies and an eagle and by all accounts looks really good after his first nine holes of the day.
"The heat is hard for me because I lose so much weight out here", said Woods.
"I hit a lot of attractive putts that were on top of the edge and then obviously hit a couple bad ones on the last hole".
"So I'm going to try to make it as hard as possible on Jim".
Woods posted an incredible 29 on his front nine, including birdieing three of his first four holes.
Leishman is projected to need at least a tie for 38th to remain inside the FedEx standings's top 30, who advance to the Tour Championship finale. "But they didn't go in today".
"I made a few putts today", Woods told the Golf Channel.
Tee times were pushed back three hours on Saturday because of overnight rain that kept falling into the morning. "I lose strength and I lose power and endurance". Before you make any 2018 BMW Championship picks or enter a daily fantasy golf tournament on FanDuel or DraftKings, you'll want to hear what the team at SportsLine has to say.
He missed a 4-foot par putt on the par-3 fifth hole and didn't convert any of the birdie putts from the 20-foot range. He was the PGA Tour rookie of the year last season after winning the Tour Championship for his second PGA Tour title.