Billy Mayfair also shot 67 in the second round and moved to 9-under-par 135. Padraig Harrington, the defending champion, climbed into the mix thanks to 67 of his own. He shares third place with first-round co-leaders Geoff Ogilvy (71) and Mathias Gronberg (71), as well as Daniel Chopra (65).
Toms stumbled out of the gate with a bogey on the first. He quickly got that stroke back with a birdie on No. 2. The 2001 PGA Champion rolled in his second birdie on the fourth to move to minus-6.
The 39-year-old birdied each of the next two holes, both par-5s on the Sunrise Course at Country Club of Mirasol. Toms made it four in a row as his birdie effort on the par-4 seventh found the bottom of the cup.
Toms, who used that birdie run to take the lead, climbed to 11 under with a 3-foot birdie putt on the 12th. After his approach bounced over the green at the 14th, Toms was unable to save par.
He came up short of the green at the 16th and again dropped a shot to par. Toms' lead was down to one over Mayfair at minus-9.
Toms found the fairway off the tee at the par-5 17th, but his ball came to rest in a divot. No matter, as he was able to smack his second shot from 228 yards out over the green. Toms calmly chipped in for eagle to jump back to minus-11.
'You know, I hit a great shot from where I was (in that divot),' said Toms. 'I was just trying to punch it down there and run it on the front of the green and it came out perfect, and it went just over the green. I had a pretty easy chip and obviously took advantage of the shot that I had and made it. A lot of emotions on that one hole.'
At the 18th, Toms missed the putting surface right. He chipped inside 7 feet, but missed the putt on the left to close out 10 under.
'I've kind of been hit or miss the past couple of weeks,' Toms said. 'I've done some really good stuff, then made a bad swing when I shouldn't. However, this golf course will do that to you. Sometimes you can't just dial it in to the perfect yardage to some of these pins. I just need to be out there making good swings and taking the results it gives me.'
Mayfair played the back nine first on Friday and parred his first seven holes. He picked up his first birdie at the 17th to get to minus-5.
The five-time winner on the PGA Tour parred five in a row around the turn. Mayfair, like Toms, birdied the fifth and sixth. The 39-year-old moved to 8 under with a birdie on the seventh. Mayfair closed with a birdie on the ninth, his last, to get within one of Toms.
Lee Westwood fired a 6-under 66 in the second round to get to 5-under-par 139. He was joined there by Stephen Ames, Paul Azinger, Jason Schultz, Luke Donald, Brian Gay, Jeff Gove and Scott Hend.
Ryuji Imada, the final of four first-round leaders, struggled to a 1-over 73 and stands at minus-4.
The cut line fell at 3-over-par 147 with 74 players moving on to the weekend.