[bhaveshnande]

In your

Код:

if (strcmp("/speed", cmdtext, true, 10) == 0)
    {
        new Float:x, Float:y, Float:z;
        GetVehicleVelocity(GetPlayerVehicleID(playerid), x, y, z);
        SetVehicleVelocity(GetPlayerVehicleID(playerid) ,x ,y+0.3 ,z);
        return 1;
    }

I guess it should be
SetVehicleVelocity(GetPlayerVehicleID(playerid) ,x=0.3 ,y+0.3 ,z+0.3);