The 14-time major champion, playing his 11th event in a comeback year after spinal fusion surgery, stood seven strokes behind co-leaders Andrew Landry and J.J. Spaun after 18 holes at TPC Potomac.
"Really didn't give myself a lot of good looks," Woods said. "I made a couple birdies, which is nice, but I have to do a better job to give myself some more chances."
Woods, unhappy with his putting since sharing 32nd at the Masters, began working last week with the new Ardmore putter and used it to replace his Scotty Cameron, the putter he used in winning 13 major titles and in his latest return after years of back pain.
"I rolled it well," Woods said. "I hit a lot of good putts. It was nice to feel that again and nice to feel the putter swing.
"I hit a lot of good putts on my line with the speed I wanted. I haven't done that in a while. I haven't been doing that. So that's the positive sign, to keep doing that. Eventually they will start rolling in."
Woods took a double bogey at the par-4 sixth but the 42-year-old US star answered with birdies at the par-4 14th and 16th holes in a mostly routine round.
"I shot about the score I should have shot," Woods said. "I didn't have anything going for the whole round. I was hanging in there and hanging in there."
Landry and Spaun each shot a bogey-free 63 to share the course record and grab a one-stroke lead over fellow Americans Billy Horschel and Andrew Putnam.
"Not too far back, 3-under is in 10th," Woods said. "Just have a few good holes early, you are right back in the game."
While his 79 career US PGA victories are three shy of Sam Snead's all-time record, Woods has not won a title since the 2013 WGC Bridgestone Invitational and last captured a major at the 2008 US Open.
Woods, who won the 2009 and 2012 Nationals when the event was played at nearby Congressional Country Club, vows he is committed to the putter change.
"I'm very committed to it," Woods said. "I've always struggled on greens that are a little on the slower side and these greens aren't very quick right now and they won't be quick in three weeks' time either (at the British Open). So it was a nice thing to move to a putter that rolls a bit quicker."
'I had to fight through'
Former world number one Woods, now ranked 82nd, sent his approach into tall weeds at the sixth, took a penalty drop and two-putted from 35 feet for double bogey.
"I just hung in there and I thought eventually I would turn it around, but I had to fight through it," Woods said.
He found the deep grass again at 10 but chipped out and dropped his fourth shot inches from the cup for a tap-in par.
Woods finally snared a birdie at 14 after landing his approach three feet from the cup, but missed a seven-foot birdie putt at 15, then responded by sinking a nine-foot birdie putt at 16.
"Overall it was a good day," Woods said. "But not the day I really wanted."
Landry won his first PGA title two months ago at the Texas Open. He also pushed Spain's Jon Rahm to a playoff in January's CareerBuilder Challenge before losing on the fourth extra hole.
Spaun, seeking his first PGA title, was a runner-up at last November's RSM Classic and took third at last month's Byron Nelson Classic after recovering from a pinched right elbow nerve.