2002 z24 running trouble

Hey guys, there's this kid here who has a 2002 z24 with some minor mods, (venom controller, exhaust,... ect) the car runs alright at idle but when driving it doesn't have power. The engine seems to be running smoothly just getting choked or somthing - It kinda seemed similar to if you would keep the e-brake on and try to dirve. His check engine light is on too. He was going to go to a garage to get a diagnostic check, -- anybody have any idea of what might be wrong?? Thanks for any help
Luke