Tensions were high in federal court in Minneapolis on Wednesday in the high-stakes legal battle that pits the Toyota Motor Corp. against the driver of a 1996 Camry and the families whose lives were forever changed by an automobile crash that left three people dead.

Toyota's lead attorney, David Graves, spent much of the afternoon on his feet during the second week of trial, repeatedly objecting to testimony about the Camry's accelerator that might lead the eight-man, six-woman jury to conclude that Toyota was at fault.

U.S. District Judge Ann Montgomery several times broke in to halt the debate and rephrase the questions posed to two experts.

The sharp divide quickly came to a head during the close of testimony by Andrew Irwin, an accident reconstructionist hired by attorneys for Koua Fong Lee, the driver who spent 2½ years in prison for criminal vehicular homicide in connection with the 2006 accident.

Lee, 37, has maintained that his Camry had inexplicably accelerated while he tried unsuccessfully to apply the brakes, and crashed into an Oldsmobile after exiting eastbound Interstate 94 at Snelling Avenue. A new attorney retained by Lee produced witnesses in 2010 who said their 1996 Camrys also experienced sudden accelerations.

Ramsey County Attorney Susan Gaertner at that time opted against a second trial and instead allowed Lee to go free.

Irwin was on the stand again Wednesday when Lee's attorney, Bob Hilliard, asked him for his opinion about a butterfly valve in a throttle mechanism that the experts hired by Ramsey County found partly open when they examined the wrecked Camry four years after the crash.

The valve is connected to the accelerator and could be a signal that the accelerator was not working properly, Hilliard maintains.

Hilliard asked: Did Irwin know the accelerator mechanism was stuck partly open?

Graves objected.

There were more questions about the "stuck" accelerator and more objections by Graves, who noted that the totaled Camry had been sitting outside uncovered in a police lot for four years before it was examined by Irwin.

The judge then turned to the jury.

"The jury is going to have to decide whether it was stuck," she told them.

Graves also objected repeatedly during the testimony of John Stilson, an Illinois automotive and safety consultant who criticized Toyota's accelerator design for the 1996 Camry.

"It is my opinion it was designed and manufactured defectively," he stated.

Stilson said that heat from the Camry engine caused two plastic pulleys to "bind" and become stuck, leading the car to accelerate on its own.

"The cause of the accident was the defect of the accelerator system," Stilson testified.

Stilson showed jurors an accelerator system he redesigned himself that he said would have prevented the pulleys from binding.

Toyota has argued that the pulleys could withstand the engine heat.

The company has argued that Lee, who had little experience driving the Camry, caused the accident himself by mistakenly hitting the gas pedal when he meant to apply the brakes.

Randy Furst • 612-673-4224

Twitter: @randyfurst