Originally Posted by Lude Acts

Clogged fuel filter? Weak fuel pump? Sounds like a "not enough fuel getting to the engine" issue. The gravity is fighting against the flow of the fuel. I suppose it could still be a bad gas cap, as the fuel pump would be sucking air with the fuel. I'd (re-) start with a new gas cap fo' sho'. FO' SHO'!!!!!!!! And a fuel filter. Those are both pretty cheap.