How about lots of crap, er residue, in the gas tank, and as soon as the level gets low enough, it starts clogging the fuel line? Then once it sits for a while, the residue settles out, and the clear fuel can run through the line.
There's supposed to be some way that you can flush out a fuel tank, although if it involves sucking on a siphon line, you can leave me out. Also the trauma these days of dumping a quarter tank of gas!
* Credit is a wonderful servant, but a terrible master. * Who's the boss --you or your credit?
FICO's: EQ 781 - TU 793 - EX 779 (from PSECU) - Done credit hunting; having fun with credit gardening. - EQ 590 on 5/14/2007