Most NFL teams would be ecstatic to be in the Indianapolis Colts' position - the AFC's lone undefeated team riding a 16-game regular-season winning streak.

Peyton Manning and company are hardly satisfied, though. With their ground game struggling and their schedule about to get much tougher, he knows they still have plenty of work to do.

The Colts will try to get their offense in gear and continue their dominance over Houston on Sunday against a Texans team looking to win its fourth straight.

Indianapolis improved to 7-0 for the fourth time in five seasons with last Sunday's 18-14 home win over San Francisco, but it wasn't an inspiring effort by the normally high-powered offense.

The Colts settled for field goals on four trips into the red zone and Manning failed to throw a TD pass for the first time since Nov. 30, 2008.

Manning finished 31 of 48 for 347 yards, but missed high, wide and even short to finish with a season-low 86.0 quarterback rating. The three-time MVP had a 118.8 passer rating in the previous five games.

"I thought we weren't quite as sharp as we have been at times,'' Manning said. "There's definitely some areas we can improve on.''

Indianapolis hasn't lost since falling 31-21 at Tennessee on Oct. 27, 2008, and needs to get better in a hurry with stiff competition looming.

The Colts only faced one team with a winning record so far - Arizona (4-3) in Week 3 - but after this contest they host New England (5-2) on Nov. 15 followed by a trip to Baltimore (4-3) and back to Houston (5-3).

"We are getting into the teeth of our schedule right now," Manning said.

Creating a ground attack would be a big help to Manning and the offense.

The Colts rushed for 61 yards on 21 attempts against the 49ers with just five plays going as long as four yards. Indianapolis ranks 30th in the NFL with an average of 87.3 rushing yards per game.

"We know what we can do. We just have to correct the mistakes we made and move forward,'' said Joseph Addai, who has not rushed for more than 64 yards.

Correcting these mistakes against a Houston rush defense that has shown vast improvement over the past few weeks could be difficult. After allowing an average of 205.0 yards on the ground in their first three games, the Texans are yielding 58.2 in the last five.

Houston defeated Buffalo 31-10 last Sunday for its third straight victory to get off to the best start in franchise history.

The Texans, who won a franchise-best four in a row last season, are in the thick of the playoff picture but a defeat in this game would give the Colts a four-game lead in the loss column.

"When you get to where your football team is pretty good, they're all big,'' Houston coach Gary Kubiak said. "It's just nice that we're to the point now where we should play in some big football games here in the second half and none bigger than the first one.''

Beating the Colts would be a big step for the Texans. Indianapolis, though, is 13-1 all-time against Houston with the loss coming on a last-second field goal in 2006.

Manning has been sensational in those contests, passing for 3,859 yards with 33 touchdowns and five interceptions. He has 17 TD passes and one pick in the last seven meetings.

Houston's Matt Schaub, who has thrown a career-best 16 touchdown passes, completed 27 of 33 passes for 236 yards with a touchdown and two interceptions in his only start against the Colts, a 30-24 loss on Sept. 23, 2007.

Schaub leads an offense that has already matched a franchise record set last season with four 400-yard games, but the unit will have a different look this week.

Tight end Owen Daniels, a favorite target of Schaub with 40 receptions for 519 yards and a team-leading five touchdowns, will miss the rest of the season after tearing a knee ligament last week.

Schaub will be joined in the backfield by running backs Steve Slaton, Ryan Moats and Chris Brown, all expected to split time.

Slaton was benched against the Bills after fumbling for a fifth time, and Moats did a stellar job as his replacement, running for a career-high 126 yards and scoring a franchise-best three touchdowns.

"They know they're all going to play and they know they're all going to be a part of what we're doing, so I just think we keep working them,'' Kubiak said.

Slaton rushed for 249 yards with three touchdowns on 30 carries in two games against Indianapolis last season.

Schaub and the offense won't have to deal with many of the Colts' best defensive players. Linebacker Tyjuan Hagler (biceps), cornerback Marlin Jackson (knee) and strong safety Bob Sanders (elbow) are all out for the season.

Veteran cornerback Kelvin Hayden is also expected to be sidelined for the next three to four weeks with a knee sprain.