Q: Hey I have a 2000 Buck Lesabre and I'm having some fuel issues I think

Fuel is a possibility but so is air induction particularly the idle air control (IAC) valve. The IAC valve may be sticking which would explain the first symptom you report which is everything was great until you simply put it in park and at idle it died. It would be good to address the battery/charging system issue so as not to complicate the diagnostic. That is be sure the battery passes a load test and that the charging system output is within factory limits, typically around 14.5 volts. If all checks out OK with the air induction system, including sensors and controls, of which the IAC is just one component, and yet the car continues to stall, check fuel system pressure. You could have a failing fuel pump, pressure regular, clogged fuel filters or plugged injectors. If, at any point, you want a certified mechanic to resolve this, please simply request a stalling diagnostic and the certified mechanic will come right to your location, find the root cause and estimate the repair.