[TMasters]

its because you didnt define the string for individual players, you defined it for all players together. if you use the string variable as global then you should visit http://forum.sa-mp.com/index.php?topic=134164.0 else do the string variable as local inside the Box function


SOLUTION

Код:

#include <a_samp>
#include <a_npc>

new Text:InfoBox[MAX_PLAYERS];
new ITimer[MAX_PLAYERS];
new IBoxString[MAX_PLAYERS][128]; // as we use it as global, we don't want any conflicts with healths of other players
new Float:VHealth[MAX_VEHICLES];

forward UInfoBox(playerid); // defined player id removes need of variable PID[];

public OnFilterScriptInit()
{
	print("\n--------------------------------------");
	print("     Vehicle Health Script     ");
	print("--------------------------------------\n");
	return 1;
}

public OnFilterScriptExit()
{
	return 1;
}

public OnPlayerExitVehicle(playerid, vehicleid)
{
 	KillTimer(ITimer[playerid]);
	TextDrawHideForPlayer(playerid, InfoBox[playerid]);
	return 1;
}

public OnPlayerStateChange(playerid, newstate, oldstate)
{
	if(newstate == PLAYER_STATE_DRIVER)
    {
  	    InfoBox[playerid] = TextDrawCreate(200.0, 360.0, " ");
		TextDrawUseBox(InfoBox[playerid],0);
		TextDrawTextSize(InfoBox[playerid], 440, 410);
		TextDrawBoxColor(InfoBox[playerid],0x00000066);
		TextDrawSetOutline(InfoBox[playerid],1);
		TextDrawLetterSize(InfoBox[playerid],0.5,1.2);
		TextDrawSetShadow(InfoBox[playerid],0);
		ITimer[playerid] = SetTimerEx("UInfoBox", 250, 1,"i",playerid); // changed the timer to 250, no need top be faster unless u use it for speed detection
	}
	else
	{
	 	KillTimer(ITimer[playerid]);
		TextDrawHideForPlayer(playerid, InfoBox[playerid]);
	}
	return 1;
}

public UInfoBox(playerid)
{
	GetVehicleHealth(GetPlayerVehicleID(playerid), VHealth[GetPlayerVehicleID(playerid)]); 	
	format(IBoxString[playerid], sizeof(IBoxString[])-1, "~r~Vehicle Health: ~y~%.1f~n~~r~", VHealth[GetPlayerVehicleID(playerid)]/10);
	TextDrawHideForPlayer(playerid, InfoBox[playerid]);
	TextDrawSetString(InfoBox[playerid], IBoxString[playerid]);
	TextDrawShowForPlayer(playerid, InfoBox[playerid]);
}

TRY IT :P I did not test it but i think its alright UPDATED!!!! Should work now with no changes made