1993 Chevy S-10 Blazer Still won't run

I have a 1993 Chevy s10 Blazer 4x4 with about 125,000. This is a follwo up to a question posted last week. We have changed most of the electrical components on the blazer - the iginition module. The fuel pump relay and we have realized that our new fuel is only giving us 15 PSI of pressure and our engine requires 55-61 PSI of pressure, we are going to change the fuel pump, again, and I was wondering if you would have any suggestions what might need to be changed if the vehicle still does not start. It will currently turn over but will start and if we spray starting fluid on the intake it will take right off until that burns off. Suggestions welcomed. Thanks