Have my fg f6 at a reputable workshop. Getting tuned with hp tuners the car idles perfectly but when they go to run it on the dyno at 2500rpm the ecu sh*t itself. The 5th cylindre is dead the ecu doesnt seem to be pulsing the injector when the injector is earthed the injector pulses, the coils are all fine. Swaped another ecu got it reflashed by ford to suit the car and now the same issue occured while the car was getting tuned. What could be causing this issue