Thanks for your replies. My flap must of broke off, and fell into the gas tank. I don't think it would cause any issues. But I have to be careful, when filling my tank. As if I try to put a few more cents of gas into it, after the pump automatically shuts off. Some gas spills out onto the ground. My 02' is actually a parts car now. As it dropped a valve, and ruined the engine. So I can take take the gas filler neck, with the intact flap, and put it on my 04'. But this looks like a big job. Need to remove the fender flare and wheel housing, to get to the back of it. Hardly seems worth it... Might as well just drop the gas tank as well, to save the fuel pump. I know these are very expensive. I am taking off everything I can, for spare parts for my 04'. Then have whats left, towed away for junk.