Parked on incline, now it cranks but no start

I drove from Illinois to Virginia a few days ago to my girlfriend's parents' house and parked on their inclined driveway. It started in the morning once, but about an hour later I tried and it would crank but not start. I bled the lines at the injectors and found that I 3 of the 5 were not getting any fuel at all. This is where I am at now. Any help is greatly appreciated. I researched this problem with others parking on an incline. So strange.