Completely remove the mat and take it for a drive, not as easy to look at your feet while driving unless you're in a parking lot. Some of those claims with the whole Toyota case came down to this, improper installation of mats.
We are having this same issue with a 2017 Chevy Trax we bought new that we have had less than a year. Initially the problem we had was it would shudder when accelerating at a light or stop sign. Then it started periodically stalling. It has just recently started randomly accelerating. This has happened twice. We have had it in to Chevy service four times. They keep telling us they find nothing wrong and if there is nothing showing up with the computer diagnostics, then "the car is operating as designed." I'm fed up with this!! Even opening a case with Customer Care has not resulted in a resolution.