Maybe it has something to do with the acceleration pedal like maybe a stripped wire that touches when not wot. Just a suggestion but like azure said check connections and possibley grounds that may be loose but go back to contact with the jerk of wot if that somewhat says something like it wiggles back in place. Sorry if i made no sense couldnt find how to explain it
1996 Mustang GT, 17x9 front and 17x10.5 cobra r replica rims, 255/40/17 front 285/40/17 rear at the moment,
o/r x-pipe flow master 40 series dump downs, cai/ram intake, 75mm c&l throttle body and plenum, pi heads and intake swap, msd wires, stock gears, untuned at the moment, no dyno numbers for now.