Washington ? A House committee on Friday questioned the rigor of Toyota’s sudden acceleration tests, challenging the automaker’s commitment to finding the causes of safety problems that have led to millions of recalled vehicles. Other lawmakers zeroed in on federal investigators’ response.

The House Energy and Commerce Committee told Toyota executive Jim Lentz in a letter that there is “an absence of documents” to show whether the company thoroughly investigated the possibility of unintended acceleration.

The committee asked who is involved with the testing and demanded that it be given quarterly reports detailing allegations of the unwanted acceleration.

“We do not understand the basis for Toyota’s repeated assertions that it is ‘confident’ there are no electronic defects contributing to incidents of sudden unintended acceleration,” wrote Chairman Henry Waxman, D-Calif., and Rep. Bart Stupak, D-Mich.