Toyota: 1990 celica GT- Sputtering, check fuel, fuel filter

Question
Well the car has been sputtering, so I changed the timing belt and fuel filter and it runs smooth but when I'm stopped or when I let go of the gas as I'm driving it starts to sputter or hesitate, when I'm stopped the idle is jumping, and if I hit the gas it hesitates before my RPM needle moves. I changed the fuel filter, ingnition coil, and the timing belt, any ideas? Could it be the fuel pump or maybe a leak in the intake?

Answer
Hello,

well the cause may be from different parts...
Check:
fuel pump
Mafs (the sensor on the airbox)
Spark plugs

OR the timing belt is not fitted correctly, maybe the cams are not "tuned" well, and the valves are not working correctly in this case.

Hope this helps!

Regards,
Jack