DOVER, Del. — Jimmie Johnson is in a slump. A big one by his standards.

He's finished two of the last three races in the garage instead of on the track. Johnson hasn't won in six races and no longer holds the Sprint Cup points lead.

Throw in a busted rear axle in the season-opening Daytona 500 and he already has two more DNF's than he did all of last year.

Johnson is suddenly hearing questions he's not accustomed to answering.

Has Johnson's luck finally run out? Have other drivers — notably the ones at Joe Gibbs Racing — finally caught up with the four-time defending champ?

Ahh, not so fast.

For all the issues that have hit Johnson's No. 48 team this season, he still has three wins and is a lock to qualify for the Chase for the championship. And no driver dominates those final 10 championship races quite like Johnson and his Hendrick Motorsports crew.

Count out that fifth title at your own risk.

Still, watching Johnson's Chevrolet limp toward the garage after getting caught up in wrecks has to have the rest of the field hoping some of that misfortune lingers well into October and November.

"We've been saying this all along with the 48 car being at the top of its game, this stuff doesn't last forever," Johnson said. "The garage area get smarter, teams, drivers, everyone is developing and trying to make their equipment faster and better."

Johnson refuses to blame NASCAR's early-season shift to the spoiler as the reason. Instead, it's been bad luck and accidents that have some thinking he might finally be vulnerable.

He's not fearful this little stretch is a sign of bad things ahead.

"We're not where we want to be," he said, "but we're still awfully competitive. We're not as worried or concerned as some of the headlines may read and some speculation that might be out there."

Johnson has finished 31st and 36th in two of his last three races. His miserable race last week at Darlington Raceway ended in a crash.

Johnson acknowledges NASCAR's change from the wing to a spoiler has been an adjustment, but crew chief Chad Knaus and the HMS team were prepared.

As Johnson has cooled, his closest competitors have ripped off hot streaks. Over Johnson's winless streak, Denny Hamlin has won three times. Kevin Harvick, who grabbed the points lead, has a win and four straight top-sevens. Kyle Busch has been steady and Johnson's HMS teammate Jeff Gordon has no wins to show for some otherwise fantastic up-front runs.

All are nipping at the shot to end Johnson's reign.

"If we can beat them in the first 10, we can beat them in the last 10," Harvick said. "It's not about winning every week. You have to run 10 races at the end of the year to pull it all together.

Jeff Burton, ninth in the standings, doesn't feel Johnson's time is up just because of some recent struggles.

"I've seen, over the last four years, times in the season where they've done just what they've done right now and been strong when it counted," he said. "So, I wouldn't count them out just yet. I do believe they're still second in points. But it's not like they're 23rd."

Johnson could start to put some of the doubts to rest with a strong performance Sunday at Dover International Speedway. He's at one of his favorite tracks on the one-mile concrete at Dover. He swept both races last year and has three other wins and 11 top-10 finishes since 2002.

Johnson did have the top practice time in Saturday's first session. He was 16th in the second session.

His history shows this "slump" will be a mere footnote to the season by the time of the finale at Homestead-Miami Speedway.

"There's still a lot of racing left and it will be fun," Johnson said.