[iPLEOMAX]

You need to use SetTimerEx, which will allow you to pass on more parameters. (ex: playerid and all..)

SetTimerEx("CarParts", 5000, false, "i", playerid);

And don't use x,y,z Position coords on AttachObjectToVehicle. It's "offset", not position.

AttachObjectToVehicle(Spo,id,0,0,1,0,0,0);