aJumpCar + ZCMD/Y_CMD + SSCANF

#include <a_samp>
#include <zcmd>
#include <sscanf2>


#define Rojo       0xFF0000FF
#define VerdeC     0x00FF00FF

new Float:Jumping[MAX_PLAYERS];

public OnFilterScriptInit()
{
	for (new i = 0; i < MAX_PLAYERS; i++)
	{
	    if (IsPlayerConnected(i) && !IsPlayerNPC(i))
	    {
	        Jumping[i] = 0.2;
	    }
	}
	return 1;
}

public OnFilterScriptExit()
{
	return 1;
}

public OnPlayerConnect(playerid)
{
    Jumping[playerid] = 0.2;
	return 1;
}
CMD:jumpcar(playerid,params[])
{
   new string[128]; new Float:jumping;
   if(sscanf(params, "f", jumping)) return SendClientMessage(playerid, Rojo, "Uso: /jumpcar [0.0 - 0.5]");
   if(jumping < 0.0 || jumping > 0.5) return SendClientMessage(playerid, Rojo, "Uso: /jumpcar [0.0 - 0.5]");
   Jumping[playerid] = jumping;
   format(string,128, "* Has puesto el salto de tu vehiculo en %0.2f", Jumping[playerid]);
   SendClientMessage(playerid, VerdeC, string);
   return 1;
}


public OnPlayerKeyStateChange(playerid, newkeys, oldkeys)
{
	if (IsPlayerInAnyVehicle(playerid) && GetPlayerState(playerid) == PLAYER_STATE_DRIVER)
	{
        if (newkeys & KEY_CROUCH)
        {
            new Float:x, Float:y, Float:z;
            GetVehicleVelocity(GetPlayerVehicleID(playerid), x, y, z);
   	        SetVehicleVelocity(GetPlayerVehicleID(playerid), x, y, z + Jumping[playerid]);
		    return 1;
		}
	}
	return 1;
}