Alex Tagliani admitted he was puzzled by how his pace tailed off in the Indianapolis 500 after his strong challenge for the lead in the opening stints.
The surprise polesitter had maintained his practice and qualifying form at first to fight for the lead with Ganassi's Scott Dixon and Dario Franchitti.
But following the third pitstops Tagliani's Sam Schmidt Motorsports car fell off the pace and he tumbled to 19th place before eventually crashing out.
"We had a really good, balanced car early on. It was nice to drive it," he said. "Then all of the sudden, it became very loose. I couldn't really get it back on track with all the tools I had in the car.
"So we were struggling with a very nervous car. In one of our pitstops, we thought we fixed it, but we didn't."
Until the handling problem struck, Tagliani was confident he could have stayed in the lead battle until the finish.
"It's a shame, because early on the car was so good I thought we had a shot at it all race long. But we kind of lost the car at some point; very curious," he said.
"When the car became loose, I don't think we were going to become a threat for Dario and Scotty. It was a shame, because early on I think we had something for them. It's something we're going to have to look at. I don't know why exactly the car became loose."