Woods stands at 5-under-par 208 while Yokoo, who also held the second-round lead, matched the top player in the game with a 2-under 69 Saturday to reach 13-under-par 200.
Woods struggled on the greens at Phoenix County Club. He three-putted for par at the fourth when after his first putt, Woods left himself with an eight-footer for birdie. Woods had a chance to cut into Yokoo's lead at the last but missed a five-foot eagle putt.
'I hit that putt right where I wanted to,' said Woods, referring to his putt at 18. 'It just didn't break they way I thought it would.
'I hit the ball well. I just didn't make the putts and I don't know what the reason is. I've been hitting good putts, but they've been skirting by the hole.'
Woods may trail by eight shots but even he knows anything is possible if he can get the flat stick rolling.
'I just need to go out there tomorrow and get some early putts,' Woods said. 'If I get some early breaks and get a little momentum going I'll have a chance.'
European Ryder Cupper and first-round leader Darren Clarke eagled the final hole to get within one stroke of the lead. He roped a 5-wood from 235 yards out to 20 feet and drained the putt to polish off a round of 65.
'The greens here are really difficult,' Clarke said. 'You have to be able to read the greens well and speed is so important. I was pleased with today's round and am looking forward to tomorrow.'
Myanmar's Zaw Moe shot a 68 on Saturday and trails by three shots. Spain's Sergio Garcia is four behind after a third-round 69.
'Unfortunately, I didn't putt as well as I would have liked,' Garcia said
David Duval, the defending champion, is five strokes off the pace after he carded a 67 on Saturday.
Full-field scores from Dunlop Phoenix Open