I recently instaled a new fuel presure regulator with my dad, after putting everything back together and tried starting it. This is the first time it's ever started really well, but when it go to an idle it'd spit and sputter and was very slow for throttle response. Being as it was really late we decided that we'd work more with it today. After letting the feul pump run but it wouldn't fire. The pump runs and there is spark but the truck won't start. Anyone have any ideas?