Crank no start

Replaced battery, fuel filter, fuel pump, spark plugs and wires, timing belt and ignition coil. I cannot get the car to start. After I did the timing belt (repairs are in order) the car started but ran rough for about a week. We use 91 octane to try and clean the system but now the car is right back where is was. Please help this was supposed to be an easy fix to get my little sister a car but it is driving me insane and that the furthest I have seen this car drive. Thank you, Vaun