> If the vehicle is fuel injected and the vapor line plugged, the chances are
> very good that the suction from the fuel pump will collapse the fuel tank.
> Vacuum has almost superman like powers. Especially on thin fuel tanks. I've
> seen it happen with mechanical pumps on beetles.

I'll second that - my Dad's diesel Rabbit did this when the vent hose 
rubbed against the alternator belt & melted closed. The tank would 
only hold about 3-4 gallons of fuel afterwards. VW covered it under 
warranty though...