Whether he stays there when everyone finishes the third round is still to be determined.
Furyk finished with five straight birdies to set the course record at Bellerive with an 8-under 62 in the second round, then followed with a 66 that put him at 12-under 198 and gave him the clubhouse lead.
Camilo Villegas, who shot 66 in the morning for a one-shot lead through 36 holes, also was 12 under and had five holes left in the third round when play was suspended by darkness.
He will have to return Sunday morning to finish his round in a tournament twice interrupted by weather. Rain kept the BMW Championship from starting until Friday, and the plan for everyone to play 36 holes on Saturday was disrupted by a 90-minute fog delay in the morning.
But it was packed with all kinds of drama.
Sergio Garcia made the first hole-in-one of his professional career, a 5-iron from 205 yards on the third hole in the morning that put him into the mix. Bart Bryant made an ace in the afternoon, on No. 13, four holes after learning he had been docked a two-shot penalty simply for opening his mouth.
Martin Laird tamped down his own pitch mark on the fringe of the 16th green during the second round, which he was not supposed to do because it was in the line of Bryants ball in the rough. The fact Bryant said, Yes when Laird asked if it was in his line meant Bryant was penalized because he allowed his line to be improved.
Laird was not disqualified because it was not his intent to help Bryant, who chipped well over the mark.
Much more steady was Furyk, who hit 24 consecutive fairways off the tee until he started to tire at the end of a long day and found the rough on the 18th hole. He could not advance it to the green, came up short with a wedge and was thrilled to sink a tricky 5-footer for bogey.
He played 36 holes and took only 128 shots. Of equal importance is that he didnt have to return Sunday morning. Villegas and Brian Gay, who was 10 under with three holes remaining, were among 23 players that were to resume the third round at 7:30 a.m.
Im tired, Furyk said. I like the idea of getting some sleep.
Villegas is keen to get his first PGA TOUR victory to accompany his marketing appeal, and this is the second straight week hell have that opportunity. At the Deutsche Bank Championship, he was one shot out of the lead going into the final round until Vijay Singh closed with a 63 to win by five shots.
The 26-year-old Colombian turned potential trouble into determination.
Sailing along in the morning, Villegas four-putted for double bogey on the ninth hole'the final three putts were inside 4 feet'and he was steaming when he left the green.
But the answer was swift'two straight birdies'and Villegas added one more from 12 feet on the 18th hole to take the lead into the third round. The tour did not make new pairings with hopes of finishing, so Furyk managed to finish 54 holes well ahead of Villegas.
Im feeling good, Villegas said. Im enjoying playing golf right now. Im playing pretty good. Im rolling in some great putts, and Im excited about tomorrow.
Anthony Kim, already a two-time winner on the PGA TOUR this year, was at 9 under with one hole to play. Right behind at 8-under 202 was a group that included K.J. Choi and D.J. Trahan, who was overpassed as a Ryder Cup pick earlier this week, his final-round 80 at the TPC Boston not helping his cause.
Phil Mickelson was 7 under and had faced a 20-foot birdie putt on the par-5 eighth hole, his 17th.
Furyk has not won since the Canadian Open last year, and he has not even led after any round since then. He has been steady and has done everything but win.
It didnt appear this would be the week when he was 1 under for the tournament on the back nine of his second round. Everything changed when he holed a wedge from 114 yards for eagle, then polished off his round with five straight birdies, none longer than 15 feet.
Through 10 (holes), I probably didnt see a 62 coming, Furyk said. And then you hole out a wedge and a whole bunch of putts go in. I was real happy about the way I hit it.
After a short break for lunch, he birdied the first hole and kept finding fairways. Furyk had warned at lunch that the hardest part of the 36-hole day is the final nine, and he was right.
He didnt swing through a 5-wood to the 235-yard 16th, and had to save par from the bunker with a 12-foot putt. Then came his only missed fairway of the third round on the final hole, but the determined, quiet fist pump when he sank the bogey putt spoke volumes.
Although it was a bogey, I ended on a good note, he said.