HOUSTON, April 5, 2014 (AFP) - Garcia, who matched the low round of the week, completed 36 holes at 12-under-par 132.
"When I look at today, I thought if I am able to shoot three, four under I will be happy," said Garcia, who won the Qatar Masters in January. "To be able to shoot seven-under in those conditions was really, really nice."
Matt Kuchar bogeyed his final hole at the $6.2 million (4.5 million euros) US PGA Tour event to close out a five-under 67 and finish a shot off the pace at 11-under 133.
Windy conditions made scoring difficult on Friday and bad weather was expected to roll in late in the day on Saturday at the Tournament Course at the Golf Club of Houston.
Players will tee off in threesomes from the first and 10th holes to try and get as many into the clubhouse as possible before the storms hit.
Three-time 2014 winner Jimmy Walker (65), Australian Matt Jones (68), Cameron Tringale (68) and Shawn Stefani (69) shared third place at eight-under. Steve Stricker (69) and Ben Curtis (70) were tied for seventh at seven-under.
Jones will play in the final threesome Saturday with Kuchar and Garcia, who eagled the par-five 13th hole after hitting his 284-yard approach shot to five feet.
Garcia, who started his round on the 10th, sandwiched his eagle between birdies on the 12 and 14 on his first nine.
He added three consecutive birdies on holes three, four and five coming in.
Garcia hit 13 of 18 greens and missed just one fairway in his round.
Garcia has finished no worse than 16th in five US PGA Tour starts this season and placed in the top 20 in his past 12 worldwide starts.
"I do feel like I'm playing nicely," Garcia said. "I feel very comfortable with my equipment. I feel comfortable with myself in and outside the golf course."
Garcia said he is not reading too much into his strong start this week as he plays his final tune-up before the Masters.
"We've seen how some weeks you can go from missing a cut comfortably to winning the next week or going from winning to missing the cut," he said. "Obviously playing nicely helps, there's no doubt about that. But every week is a different world."
Both of the first-round co-leaders struggled Friday, as Bill Haas stumbled to a two-over 74 to fall into a share of 13th place at five-under.
Charley Hoffman posted a four-over 76 to fall into a group of players tied for 27th at three-under 141.
Leading second-round scores on Friday in the US PGA Tour $6.2 million (4.5 million euros) Houston Open (USA unless noted, par-72):
132 - Sergio Garcia (ESP) 67-65
133 - Matt Kuchar 66-67
136 - Matt Jones 68-68, Cameron Tringale 68-68, Shawn Stefani 67-69, Jimmy Walker 71-65
137 - Steve Stricker 68-69, Ben Curtis 67-70
138 - Ryan Palmer 70-68, Jason Gore 67-71, Jim Renner 66-72, Phil Mickelson 68-70
139 - Erik Compton 66-73, Bill Haas 65-74, Brice Garnett 68-71, J.B. Holmes 66-73, Retief Goosen (RSA) 68-71
140 - Justin Hicks 67-73, Nicholas Thompson 71-69, Freddie Jacobson (SWE) 68-72, Martin Flores 68-72, Michael Thompson 67-73, Rickie Fowler 70-70, Chris Stroud 68-72, Camilo Villegas (COL) 67-73, Michael Putnam 68-72