99 Jetta Leaking gas
 

I have a 99 Jetta that leaks gas out of the rear passenger side after it runs for a couple minutes. I jacked it up to look at that side but it doesn't leak when that side is jacked up. When it it sitting normal it pretty much pours out from that side. My brother thinks it may be an o-ring at the top of the gas tank but before I try taking it apart does anyone have any suggestions? I saw somewhere that that year has a faulty fuel tank filler neck. It's bad enough that I can't drive it.