Tony Stewart's dissatisfaction with NASCAR's new rules reducing downforce and horsepower aren't to blame for his two-year slump on the Sprint Car Series circuit.

What he sees in the mirror is.

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NASCAR Talk, on NBCSports.com, reported on Stewart's interview with The Associated Press before Sunday's Toyota/Save Mart 350 at Sonoma Raceway in Sonoma, Calif., that exposed as much confusion as frustration.

When asked where his confidence level is right now - Stewart hasn't won a NASCAR race since June 2, 2013, he said, "What's that? I should Google that and see if I can find the meaning of that word. I don't have any confidence."

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But in the same interview, Stewart says he considers himself a factor in every race he enters.

"Every week we come here, we are optimistic we are going to have a good week," Stewart said. "There's not a week that I show up and don't think I can win."

But his doubts return almost in the next breath.

"Chad (crew chief Johnston) shows up every week trying something different," Stewart said. "I feel like I'm holding him back. I'm holding this team back."

Stewart is on a drivers council that meets with NASCAR officials to discuss ways to improve on-track performance. The racing body will experiment with a lower downforce package for the July 11 race at Kentucky Speedway, Fox Sports reported, which could help Stewart with his struggles that have left him 26th in the Sprint Car Series standings after Sunday's race.

But he stressed a reduction on aerodynamics as well. That has been the source of the issue in the difficulty of trying to pass cars during a race, according to The AP.

"Make the aero not as important and make the mechanical grip more important," the co-owner of Stewart-Haas Racing said. "Mechanical grip doesn't know where the air is, doesn't know if there's a car in front of you or behind you or whenever. That's my two cents, and it comes from 37 years of driving 25 different types of race cars, but that's apparently not enough information for them to consider that valid."

If NASCAR heeds Stewart's advice, whether he can again become a factor in the Chase for the Cup will be under even closer scrutiny.