i have a 2000 gt and i installed a 2003 engine,i also used the engine harness that went with the 03 motor.i still have the 2000 computer in the car and i was wondering if this would or could cause misfire problems??? i have changed coils,plugs,camshaft position sensor and injectors and so far nothing has helped! it will clear up for a second the starts missing again...i'm gettin ready to set fire to it b/c i have worked on it for 4 days and spent 1300 bucks...needless to say i'm aggravated...help me out guys!!!