I/we had the same problem and turned out to be the mat. I have secured the mats now using Rolson Non-Slip Mat between fitted carpet and mat. This has worked for us now over 3 years.
John
had the exact same with the floor mat catching under the go faster pedal, squeeky bum at that point
If this is common, this needs to be reported. Previous MX5s have been recalled for exactly the same kind of issue (moving factory floor mats).
^^^ they can be fixed down, user error if this is the case.
Mine still has the original Mazda mats, supplied when I got the car (then new) back in 2012 as part of the deal I negotiated with the salesman. The driver’s mat has two circular holes which locate very securely onto two pegs, each of those are on plastic mouldings fastened to the part of the seat frame which doesn’t move.
I’ve never had any problems with the mat slipping in the MX-5 - although this did happen to me in another vehicle a long time ago; after a very worrying couple of seconds when the pedals suddenly weren’t working properly, luckily I quickly realised what had happened & shoved the mat out of the way. I’ve always been very careful with car mats after that.
https://www.theverge.com/2016/3/16/11246524/maserati-recall-march-2016-car-speed-problems
Dodgy mats contributed towards Toyota being fined $1.2bn.