Toyota earlier this week provided an update on progress regarding its accelerator-related recalls, and it's now more confidently pushing back on assertions that the automaker's electronic throttle controls might have caused unintended acceleration.

The automaker said that it's reviewed about 4,200 vehicles whose drivers had claimed instances of sudden acceleration, finding no evidence of an electronic flaw.

The rough going isn't altogether over for Toyota. The auto-insurance giant Allstate—after failing to reach a satisfactory settlement with the automaker—alleges that a number of accidents were caused by the recall-related defects, and it's sued Toyota Motor Corp., in an attempt to recoup damages for acceleration-related claims that it has already paid.

Allstate says that it has paid about $3 million in all toward claims that were caused, allegedly, by sudden acceleration—including 270 claims, going back to January 2007, and one for more than $60,000, involving a 2009 Lexus ES 350 in Beverly Hills. Allstate blames sudden acceleration for a total of 725 accidents, 304 injuries, and 18 fatalities, reports Bloomberg.

According to the LA Times, the suit charges that "certain of Toyota's cars and trucks have a defect that causes sudden uncontrolled acceleration to speeds of up to 100 miles per hour or more," as well as "defective electronics and the absence of a fail-safe, such as a brake-to-idle override system."

All of Toyota's 2011 model-year vehicles—including the Toyota, Lexus, and Scion brands—with so-called Smart Stop Technology, which allows the brake pedal to override the throttle. Also for 2011, enhanced Event Data Recorders (EDR) will be included on all vehicles from the automaker.

[Toyota; LA Times; Bloomberg]