[yezizhu]

Stupid me, I think I know what's the major bug.
You need to store vehicleid in enumeration

Example

pawn Код:

#define INVALID_CAR_ID (-1)
enum CarsInfo{
  //your old stuff
  Cars_Vecid
};
new Cars[...][CarsInfo];

stock Car_getVecCarID(vehicleid){
  for(new i,j = sizeof(Cars);i < j;i++)
    if(Cars[i][Car_VecID] == vehicleid) return i;
  return INVALID_CAR_ID;
}

//OnGameModeInit
Loop{
  Cars[i][Cars_VecID] = INVALID_CAR_ID
}
Cars[id][Cars_Vecid] = CreateVehicle//must use createvehicle


//OnPlayerEnterVehicle
new vecCarid = Car_getVecCarID(vehicleid);
if(vecCarID != INVALID_CAR_ID){
    //use Cars[vecCarID][...]

Same as buy/sell cars.