1999 Expedition will not start reliably

The engine turns over every time I try to start it. If it is going to start it does so immediately. If it does not start it requires starting fluid and or a jump after I have exhausted the battery.
ANY ideas?

Hopefully you have it figured out by now, but it sounds like it has to be fuel related, not holding fuel pressure a weak fuel pump or a bad connection to the fuel pump and once running (or jumped) there is enough voltage to overcome the iffy connection. I'd start by checking fuel pressure cycle the key on/off a couple of times and see if it holds pressure, also check your fuel pressure at idle (30 - 45 psi IIRC.) You could also check your battery voltage when turning it over, it could be your battery is weak and doesn't have to voltage to run the fuel pump well enough while cranking.

Thanks for your help. I had already solved the issue. The fuel pump was failing.