Update for people with this hesitiation problem:
I got the fuel pump replaced which helped (The engine check light had an error code of "low fuel pressure" ), but the problem is still there.
It now only happens when the car has been running for 30mins+ or hot (in traffic).
I disconnected the battery completely and left it for about 1 hour to reset the ECU. Now, the hesitation is not as bad and I can drive around normally with no problems unless Im going up a steep hill or accelerate hard.
Im replacing the spark plugs and fuel filter tomorrow and see what that does.
On another note, if you have a GDI engine never run it on 91 octane fuel. Run it on 96 minimum (I use 98)