Mike Springer posted a 9-under 63 in the second round and is alone in third place at minus-10. PGA Tour member Carl Paulson is in fourth at 9-under-par 135 after a 68 on Friday.
Garrigus collected a pair of birdies in his first two holes, then knocked a 6-iron to five feet to set up birdie at the sixth. He added another birdie at No. 7 before a closing front-nine birdie at the ninth.
Garrigus picked up where he started on the back nine at Le Triomphe. He birdied the 10th, ran home a 40-footer for birdie at the 11th, then chipped in for birdie at No. 13.
The 26-year-old from Idaho squandered opportunities in the closing stretch. Garrigus made the green in two at the 540-yard, par-5 14th but three-putted for par. He bogeyed the 17th hole to erase what was a three-stroke advantage.
'It was fun today,' said Garrigus. 'I did not expect to shoot 66 or 65 and be leading the tournament. I just wanted to get myself in position to have a chance on Sunday.'
Walker, who won the Panama Championship earlier this season, collected nine birdies, all from inside 15 feet, and one bogey in a round of 8-under-par 64.
'I felt like today was the day to get it going,' said Walker. 'The weekend is a lot of fun, time to get the emotions going. People have to step it up and play some golf.'
Darron Stiles (66), Rick Price (67) and Jon Mills (67) share fifth place at 8-under-par 136. First-round leader Guy Boros managed an even-par 72 and is knotted in eighth with Steve Haskins (67) and Scott Gutschewski (66) at minus-7.
The 36-hole cut fell at 2-under-par 142 and among those who did not qualify for the weekend were: former PGA Tour winners Garrett Willis (143) and Michael Clark II (144) and defending champion Brett Wetterich (146).