So, why did her car do that? Well, she'd discovered some sort of shenanigan involving Express Mail contracts with Evergreen Airways. Don't believe she ever got a chance to show up for a couple of hearings on the matter.
This later turned into a whiz-bang scandal on its own so it didn't really help the crooks to try to kill her.
Now, regarding the stories about Toyotas with stuck accelerator peddles, they're probably all true, but I think you'd be better off investigating the manufacturers' personnel rosters to see if anybody there had a mob family connection.
There may have been a few gas pedals that got stuck in the floor mat, but I would bet that nearly all these crashes were caused by driver error.