format(string, sizeof(string),"Pos=%.1f,%.1f,%.1f\n",PlayerInfo[playerid][pPosx],PlayerInfo[playerid][pPosy],PlayerInfo[playerid][pPosz]);

forward split(const strsrc[], strdest[][], delimiter);

public split(const strsrc[], strdest[][], delimiter)
{
    new i, li;
    new aNum;
    new len;
    while(i <= strlen(strsrc)){
        if(strsrc[i]==delimiter || i==strlen(strsrc)){
            len = strmid(strdest[aNum], strsrc, li, i, 128);
            strdest[aNum][len] = 0;
            li = i+1;
            aNum++;
        }
        i++;
    }
    return 1;
}

new newstr[3][75];
split(string[5], newstr, ",")
//I'd recommend using sscanf but your choice.
//If you want to use sscanf, use the following lines
//Plugin (If you have it): sscanf(string[5], "p<,>fff", X, Y, Z);
//Normal : sscanf(string[5], "p,fff", X, Y, Z);
new Float:X, Float:Y, Float:Z;
X = Floatstr(newstr[0]);
Y = Floatstr(newstr[1]);
Z = Floatstr(newstr[2]);