WASHINGTON (June 11)— W.J. "Billy" Tauzin, R-La., House Energy and Commerce Committee chairman, has sent a letter to the National Highway Traffic Safety Administration asking it to answer a series of questions regarding the steering and stability of the Ford Explorer. Although stopping short of calling for a formal investigation, Tauzin accused the agency of avoiding the question of "whether the problem with the Firestone tires is solely a tire issue, or whether it is a tire-vehicle application issue." Bridgestone/Firestone Inc. CEO John T. Lampe visited Tauzin and other lawmakers over the last couple of weeks with the results of a company-funded study showing an oversteer problem with some Ford Explorers. Ford Motor Co. continues to insist Firestone tires alone were at fault in the accidents which killed 174 people.