SAN FRANCISCO (MarketWatch) -- Toyota Motor Corp. /quotes/comstock/13*!tm/quotes/nls/tm (TM 76.99, +0.05, +0.06%) held a press conference on Monday aimed at debunking a previous study from a Southern Illinois University professor that concluded the automaker's sudden acceleration woes could be caused by an electronic malfunction. Chris Gerdes, a professor of mechanical engineering at Stanford University, was on hand to clear up what he described as "misinterpretations [that] are driving public fear and public policy." He added that they could not replicate a circuit malfunction under actual driving conditions and that some of the conclusions drawn in the earlier study could lead to "misguided policy and unwarranted fear." Toyota shares added 1.1% to $77.79 in midday trading.