Hold the phone.
Your 98.5 does not have the returnless system. Removing the fuel pump screen seldom has any benefit unless you have the returnless system, which did not come into use until mid 99.
The Focus smart pump probably is not an answer for your return system.
Start over. Change the fuel filter. If problem persists, find a fuel pressure gauge to hook up and drive so that you can see if the fuel pressure drops off when it is acting up. If it is, you probably do need a fuel pump (remember to change the fuel filter before testing the fuel pressure).
