intermittent stalling

Hi, So here is my situation. I was driving my 2005 gt turbo with 100k ,on
near empty (well aware that is foolish). I decelerated into a turn and the car
died, it started again but then began sputtering and dying on me
periodically. If i let it sit for 15+ minutes it would run perfect for various
lengths of time, also I found if I could nurse the gas staying under 2k RPM i
could usually make it to my destination but once i stopped it rarely restart ,  
until it sat. I jumped to the conclusion , i clogged the filter and after a couple
weeks of contending with it, I had a friend drop the tank  just to discover the
integrated filter pump assembly was not something he had seen and there
was no simple filter to replace. However , the gas a, take and and spreen
seemed spotless and I wasn't prepared to by the part so he buttoned it up
again and it ran great for a day or two. So i started thinking it had
something to do with air in the system , but then it started again, similar but
different, now it runs great, but then begins a rhythmic stall, not a sputter
like , like voom, voom, voom, voom  (great special effect huh?) but still fall
off if i try to give it too much gas and when it stalls now it will not restart
...until it sits. i did the dash cheat to get the codes and i got back 300-
misfire , 340- cam signal, 32 heater circuit high volt, 452 and i think this is
the one related ..fuel pressure sensor low voltage...those are the codes if
not in proper order. Now by battery is a piece and needs to be replaced
and i belive this problem is more prevalent at night.....could this be a low
power to the pump or sensors causing a shut down? I just have a feeling if i
turn over to the shop the diagnosis and process of ulim is gonna cost me
500.00+  amy ideas? miracle cures lol?