i have used (12v 1 Amp bulb) and (12v 1.3 Amp - motor), and it's works normally, i have got full 6Amp passes through MOSFET and 12v regulated.
Works normally? Did you even measure the voltage at all?
Use no load, 10mA, 100mA and 3A loads, for example. Then measure how stable is voltage with the load changing. What you wrote is just plain stupid in assessing if it works well. "
motor is rotating, must be a damn good circuit"