CHARLOTTE, N.C. - Joe Gibbs likes to say that, unlike many of his rival NASCAR team owners, racing is the family business and success is measured in victories and championships.

Well, Coach, engine issues in each of the first five races this season is a clear sign that the family business is struggling.

"It's obviously a concern, and it's one of the hardest things any team does, is build motors consistently," J.D. Gibbs, president of Joe Gibbs Racing, said Monday. "But I feel good about our guys because in years past, we've had similar issues come up, and have been OK. It's just going to take some homework."

Not one of Joe Gibbs Racing's three Sprint Cup teams has been immune from the rash of engine problems that began with the season-opening Daytona 500. In fairness to the JGR engine builders, it was driver error - a missed shift by Denny Hamlin - that blew the first engine of the year.

But then Joey Logano's engine failed at Phoenix, Kyle Busch's blew at Las Vegas and Logano ran most of Bristol short on power. Most recently, Hamlin's engine failed 105 laps into Sunday's race at California. It led to a 39th-place finish that dropped him four spots in the standings to 21st.

It would be easy to say there's no cause for worry about Hamlin, especially with the series heading this weekend to Martinsville Speedway. A four-time Martinsville winner, including the last three races, Hamlin should be fine at a track where engines are not usually an issue. But since reliability - specifically, a lack of it - is the JGR issue, he can't be certain his engine will last an entire race.

"For some reason, our stuff is struggling to (stay) together," Hamlin said Sunday.

What's puzzling is that JGR can't get a handle on the problem, which is originating in the valve train. Parts seem to be breaking in the engines of all three JGR cars on a weekly basis, forcing repairs the morning of the races and, in some cases, last-minute engine changes.

"If it were just one issue, OK, it's one fix," J.D. Gibbs said. "But when you have several different issues, it's more difficult. We've already corrected some, but there's different concerns and different projects. Some are easy and some are more involved."

In any case, this is unacceptable for an organization that expects to compete for championships every year, and it apparently led to a contentious team meeting with Joe Gibbs after the Las Vegas race. But Sunday showed that nothing has improved in the two weeks since, and the ones suffering are the drivers.

Busch and Hamlin are legitimate title contenders, and Hamlin waged a furious title fight with Jimmie Johnson last season before falling short in the season finale. So JGR came into the year expecting Busch and Hamlin to both race for the title, and for Logano to grab one of the 12 spots in the Chase for the Sprint Cup Championship.

The drivers have the talent, and the crews are clearly building competitive race cars, but it wouldn't matter if they were piloting rocket ships if the equipment can't make it to the checkered flag.

Busch, who led a race-high 151 of 200 laps Sunday to ironically earn JGR head engineer Mark Cronquist the "engine builder of the race" award, said he knows the engine shop is working hard to get a handle on the problems.

"It's not like you'll find something and maybe get it fixed in a week, but we certainly wish we would have been able to get it done by now," Busch said. "I know Mark is doing the best he can. We'll work on it. That's all I can say."

But the organization doesn't exactly have a reputation for the quick fix.

Mechanical problems have plagued JGR teams in the past, and victories have often been the Band-Aid that covers many of those ailments. Things can't be that bad when a team is winning races, right?

Wrong. Fuel mileage issues plagued the team all of last year, and despite the glaring deficiency, the problem clearly had not been solved by season's end. While many argue that the cockiness of Hamlin and crew chief Mike Ford cost them the championship last season, the title may actually have been lost because Hamlin's fuel mileage wasn't as good as Johnson's in the next-to-last race of the year.

Fast-forward to this season and there's no evidence of improvement in the fuel mileage category. Consider that crew chief Dave Rogers was telling Busch, who had dominated Sunday's race before fading to third, to conserve gas in case of unplanned extra laps.

Many, including Hamlin, have assumed that Toyota will help JGR sort out its issues. But it's much more complicated than simply asking the California-based engineers for assistance.

Toyota Racing Development builds the engines for Michael Waltrip Racing and Red Bull Racing, but JGR does everything in house. Paranoia, competitive advantage and trademark protection are the likely reasons why the two entities don't freely exchange information, so it's not as if TRD can simply figure out what needs to be fixed.

And while it may be easy to blame a Toyota part here or there for JGR's problems, it would be a hard argument to win given that engine failures haven't been an issue for the Red Bull and Waltrip cars this season.

Nope, the only engines breaking are from a championship-caliber team that can't put a finger on what's going on.

"It's of the same nature, but not the same problem every single time. That's what's so questionable about it - what the heck is going on?" Hamlin asked. "We've got our work cut out for us. We need to prove at this point that we can finish a race."

Jenna Fryer covers NASCAR for The Associated Press. Contact her at jfryer@ap.org.