[maramizo]

You have to get the vehicle IDs AFTER you spawn the vehicles, let me help you.

pawn Code:

new autohauscars[41];

//Where you spawn the vehicles:
autohauscars[0] = CreateVehicle(//first vehicle)
autohauscars[1] = CreateVehicle(//second vehicle, etc.)
//Until autohauscars[41] = CreateVehicle(.

IsAutohausCar(carid)
{
    new g;
    for(g=0; g<41; g++)
    {
        if(autohauscars[g] == carid) return g;
    }
    return -1;
}

This code should work perfectly if you edit the CreateVehicles as I told you to.