as such with it being fly by wire there shouldn't be much of a delay as it's a digital interface...so to speak but it shouldn't be so noticable as being put yer foot down and a noticable period later the car responds.... maybe a dodgy batch of sensors???... pedal end is basically a potentiometer at the end of the day....may well be that some aren't as sensitive as they should be..
let me know how you get on at the stealers mate..