For years, Toyota Motor Corp. has investigated complaints from drivers saying their Toyota and Lexus vehicles accelerated all by themselves, and the company has identified essentially one cause. The trouble, according to Toyota, occurs when loose or ill-fitting floor mats, carpet covers or detached trim jam the gas pedal.

But after a highly publicized crash in August that killed four people when the driver lost control of a Lexus sedan, Toyota has come under intense pressure to reduce the risk of unintended acceleration. [What's more...]