Tony Stewart sure consistency will come amid mixed NASCAR Sprint Cup title defence

Although Stewart is still in the top 10 in the drivers' standings, his wins and top five finishes have been punctuated by lacklustre races and incidents.

Stewart was able to carry his 2011 momentum into the early part of this season, claiming two wins out of the first five races, but since his latest victory at Fontana, he has slid down from fourth down to ninth in the points.

"We have been pretty inconsistent," Stewart admitted. "We have had some really good runs and we have had some races that we are still scratching our heads about."

Following his 2011 title success, Stewart replaced crew chief Darian Grubb, who has also won two races this year in his new role with Joe Gibbs Racing's Denny Hamlin, with former Penske man Steve Addington.

"We are working through different packages and trying to find the balance that I like," said Stewart. "Steve and I are still just getting to a lot of these tracks for the first time. It's that growing pain of getting somewhere with a new guy."

This weekend the Cup series competes at Dover, where Stewart had his worst finish during last year's Chase after struggling with handling. Kurt Busch claimed victory at the 'Monster Mile' back then, when Addington was his crew chief.

Stewart remains calm about his chances of getting back on a consistent run as the regular season enters its second half and the hotter months of the year, when he usually excels.

"We know we can do it, it's just finding the combination and what works at some of the tracks isn't going to work at other tracks," said Stewart. "We just have to keep working at it, trying to figure out what we need at the places that we are struggling."

Stewart's team-mate Ryan Newman, also a winner this year, is currently 13th in the drivers' standings.