What could be wrong with my engine? "hiccups"

[kylebrock7]

Hi, i have a 1996 four winns 240 horizon. its got a 5.8l fuel injected ford 351. we took it to the four winns dealer and they couldnt diagnose further until we replaced the fuel injectors. what happens is when we rev in neutral or while in gear, it starts "hiccuping". we ran from new fuel so it couldnt be a fuel problem. heres a video of us revving it while its in neutral.

http://www.youtube.com/watch?v=hk586WUoTSo

thanks, if you need more into ill try to provide it