Retief Goosen, the 2001 U.S. Open winner, held a two-shot lead but came undone with a bogey at 17. He finished with a 67 and is alone in third place at 6-under-par 136, followed by Chris Riley, who trails Goosen by a single stroke after a second-round 68.
With the Tour Championship at Champions Golf Club reserved for the top 31 on the PGA Tour money list and serving as the final event of the season, most eyes were focused on the battle between Tiger Woods and Vijay Singh for the money title and Player of the Year honors.
The two, paired together in Thursday's first round, struggled a bit in the first round but bounced back on Friday. Woods, a five-time winner this season who trails Singh in the money race, put up his second 70 in as many days and is tied for 12th at 2-under-par 140.
Woods birdied the par-5 fifth then sank a four-footer for birdie at the 13th. He bogeyed the 15th to fall a notch, but the No. 1 player in the world and 1999 Tour Championship winner is still in striking distance.
'I feel like I'm playing well,' said Woods. 'I hit a lot of good, solid shots today. I hit numerous good putts, but nothing went in. Overall, I feel like I really played solid.'
Singh, a four-time victor in '03 and the leading money winner, mixed four birdies and a bogey for a round of 3-under 68. He is 1 under par for the championship and tied for 16th place.
'That was the easiest 68 I could have shot,' said Singh, who won last year at East Lake Golf Club in Atlanta, Georgia. 'I left a lot of shots out there, but it's very hard to read the greens.'
In Friday's action, the leaderboard became bunched tightly several times, once with eight players tied for first. The greens at Champions Golf Club, bigger than most on the PGA Tour, have provided problems for the players, but Howell was able to handle it all and move ahead of the field.
He parred his first eight holes Friday when several players were moving around the top of the leaderboard. At the par-5 ninth, Howell ran in a short birdie putt to reach 5 under par for the tournament.
Howell, who shared the first-round lead with Kenny Perry, ran into some trouble at the par-3 12th. His tee ball went almost 40 yards right of the putting surface, and his chip came up 50 feet short of the stick. Howell blasted his par-saving putt four feet past the hole, but made the comebacker to save bogey.
Howell, winless in 2003 but 27th on the tour's money list, rebounded from the bogey in a big way. He played his second to 12 feet at the par-5 13th and drained the eagle putt to go to minus-6 and claim a share of first place.
'The eagle was really big for me,' said Howell, who finished second to Singh last year at East Lake Golf Club. 'It was a big boost for me. That really helped get the round in pretty good.'
Howell was not done. At the 14th, he hit an 8-iron from 189 yards that landed 10 feet from the hole. Howell canned the putt to go to 7 under and one ahead of the rest. Another 8-iron at the 16th resulted in another 10-footer for birdie and Howell polished off his sixth consecutive round in the 60s in this event.
'I went out there today like it was yesterday, like it was the first round,' said Howell. 'It's not an easy golf course, it's definitely not an easy format because everybody is bunched right in there together and you have an idea of what everybody's doing.'
Funk was 4 under for the tournament until he reached the par-5 13th. He birdied that hole then hit his approach to tap-in range at 14 for back-to-back birdies.
At the par-4 closing hole, Funk knocked his second to seven feet and cashed in on the birdie putt to go to 7 under and take sole possession of second place.
'I just played a real solid round today,' said Funk. 'Yesterday, in mid-round, my caddie told me I was standing a little too far away from it and I made a little adjustment on the tee. I've driven the ball a lot better since. That's key here - you've got to keep it in the fairway.'
Goosen, who won last week in Tampa, became a contender thanks to three birdies in a four-hole span starting at the 13th. He got it to 7 under but drove well right into the trees at 17 and canned a 12-footer just to save bogey.
'I probably played better yesterday,' admitted Goosen. 'I got away with a couple of good lies and here we are.'
David Toms, the 2001 PGA Champion, Justin Leonard, the 1997 British Open winner, each shot rounds of 2-under 69 to join Chris DiMarco, who shot a 70, in a tie for fifth at minus-4.
Ernie Els, Steve Flesch, Jonathan Kaye and PGA runner-up Chad Campbell share eighth at 3-under-par 139.
Joining Woods in a tie for 12th are Perry, who struggled to a 2-over 73, Bob Tway (68) and Davis Love III (67), a four-time winner in 2003 who can become a factor in the Player of the Year race if he wins on Sunday.