If you're talking about the race start, it takes time/practice to start without loosing too much rpm (i.e., modulate the clutch to avoid spinning and keep rpm in the right zone). If you don't use clutch, try to use launch control button (dunno if the Metalmoro has one).
If on the other hand you're not talking about the race start, then the only thing I can think of is to check if you don't have pit limiter engaged by mistake or maybe try to reduce the AI strength a little.