Please help!! unknown engine problem

[2003_bugeye_wrx]

hi im new to the forum and my 2003 subaru impreza wrx bugeye has a problem
when im on the the road and i try to pass someone and i step on the gas pedal quickly
my car does not go, it doesn't respond but then i let go and step on it slowly then it responds.
i think its the fuel injectors but im not sure i need help and the car has a new engine in it
someone please help.

[MainFrame]

What are the mods? Who did the new engine? When did the problem start? Who is your tuner?

[SD_GR]

If the revs climb but the car won't accelerate it's the clutch.