Brad Sutterfield shot a 4-under 67 to move into second place at minus-4. Rob McMillan, Kris Mikkelsen and Steve Scott each shot rounds of 3-under 68 to move into a share of third place at 2-under-par 140.
The first round was completed Friday morning after 12 players were left on the course Thursday night when play was halted due to darkness.
Pettitt opened on the front nine of Whitney Oaks Golf Course and got off to a quick start. He picked up back-to-back birdies from the second to get to 5 under.
However, he dropped a stroke at the par-3 fourth. After running off eight straight pars, Pettitt birdied the 13th for the second straight day to get back to minus-5.
Pettitt parred three straight holes before dropping another shot at the 17th. He erased that mistake and grabbed the lead when he birdied the par-4 18th.
Joe Acosta, Jr. and Shawn Kelly head a group of players tied in sixth place at 1-under-par 141. They are joined there by Matt Hansen, Casey Martin, Doug McGuigan and Alex Rocha.
First-round leader Craig Taylor stumbled to a 4-over 75 Friday. He stands at even-par 142, where he is tied with Chris Wisler, Rafael Gemoets and Kyle Kovacs among others.
The Golf Channel's Big Break winner, Justin Peters, failed to make the cut despite an early eagle at the par-5 third. A birdie at the 17th got him to within one of the cut line but his birdie putt at the last slid by the cup. He will be in action at next week's E-Loan Central Valley Classic.
Fellow Big Break contestant Anthony Sorentino, who was in the field on a sponsor's exemption, didn't fare as well. Although he too missed the cut, Sorentino never found his game after a disappointing first round 9-over-par 80. He then managed only a 7-over 78 in Friday's second round.
Editor's Note: Information from the Sports Network was used in this article.