2001 Saturn L300 Fuel Supply Problem

The first problem I noticed was when I was returning from a rather long trip, I stopped at a rest area and when I was ready to go, the engine wouldn't start, it turned over fine but wouldn't fire. After I had let it set for about an hour, it started right up and I continued for approx 20 miles and it just shut off, no warnings just quit. Prior to this there had never been any lights on in the dash panel, but following the rest area problem the check engine soon light was on. After I had called for a tow, approx 45 Mins, it started again, but I wasn't about to chance it any further. I had it towed to my home and ran some tests on it. The fuel pressure was 45 lbs on the fuel rail, so I checked the filter and it was bad, so I replace it and then checked it again, still 45 Lbs. I check the fuel tank and the wasn't any pressure in it at all. I ran a complete scan on this car with a code reader and everything checked out fine. As I have worked on this thing it keeps getting less and less running time when I start it, now it'll run about 6 min's before it shuts down, then after a while it starts back up again. Any ideas what I'm dealing with here, I'm wide open for suggestions and completly stuck. Thank you.