Lundy, who hadn't played in the past three games, had a touchdown early in the fourth quarter that extended the lead to 17-7. No Houston running back had gained 60 yards rushing before Sunday and the Texans managed just 34 yards rushing last week.
Houston's defense, allowing a league-worst 418 yards a game coming into the game, forced two turnovers -- both of which led to touchdowns -- and held the Jaguars to 220 yards.
The Jaguars (3-3) trailed 10-7 and had a first down inside the 30 when Antwan Peek forced Fred Taylor 's fumble, which No. 1 pick Williams recovered. The fumble was Taylor's first since 2004 and Williams' first career recovery.
"It really felt like that gave this team a boost of energy," Williams said. "After that, everything started clicking. It was a big momentum change and I was glad to be a part of it."
Lundy had his first career touchdown and became the first Houston running back to score this season when he ran in from the 2 in the fourth. His 29-yard run -- a career high -- four plays earlier got the Texans to the 15.
Ron Dayne had started the last two games for Houston, but was inactive, as coach Gary Kubiak said he wanted to give Lundy and Samkon Gado another shot.
"I was worried about him after the first couple of weeks that the overload had slowed him down and he wasn't reacting," Kubiak said of Lundy. "Sometimes you have to let players sit back and watch a week or two so that they calm down. He played with great presence today."
On Jacksonville's first play after the score, Demarcus Faggins knocked the ball out of Ernest Wilford 's hands and the Texans recovered. It was the 2006 debut for Faggins, who missed the first five games with a fractured foot.
Faggins said Wilford was holding the ball out every time he caught it.
"I said, 'OK, you do it again, I'm going to get it. I'm going to make sure I'm going to try to strip the ball when I see it,"' Faggins said. "And it happened. That was a turnaround right there. That's what kind of sealed the deal."
Jaguars quarterback Byron Leftwich, who entered the game with a sore left ankle, may have realized it was going to be a long day when his foot got tangled up with his center and he fell into the splits before being hit by Williams on Jacksonville's first drive.
Things didn't get much better from there as he often underthrew or overthrew receivers and finished 14 of 28 for 125 yards.
Leftwich denied that his ankle affected his play.
"I was just a little off today," he said. "I didn't play my best football today. I don't know why. I was OK, I wasn't hurt."
The only time Jacksonville was able to get anything done was in the third quarter when Maurice Jones-Drew bulled in from 1 yard out for the touchdown. The nine play, 70-yard drive was one yard less than Jacksonville's total yardage in the first half.
Jacksonville's next drive was stopped when Ryans tipped a pass by Leftwich on third down. Ryans, a linebacker who leads the Texans with 47 tackles this season, had six in this game.
Houston's third-quarter woes continued as they have been outscored 48-0 in that period. But unlike last week in a 34-6 loss to Dallas in which they had a halftime lead, they didn't collapse after a tough third quarter.
"I got real emotional with the players and told them it was about the fight," Kubiak said. "I told them the only one who was going to save them was themselves. I told them to get out there and fight through this."