Thread: swapped motors

ive got a 93 G20 put a jdm motor in it and the car had emissions on it but the new motor does not i hooked everything up and it wont rev past 2500rpm like its the rev limiter i read that if u unhook the battery it would reset the ecu didnt do anything then i read it could be the mass air flow sensor but the car ran fine with the old motor but ive double checkd everything and dont know what it is and the check engine light isnt on so i dont think i miss anything but i got to get it figured out