I assume you actually mean the Evaporative Emissions readiness tests don't complete. This could be related to your P0171 and P0174 codes.
These codes have been addressed a few times. I'm too lazy to retype everything, so I'm going to suggest you use the "Search this forum" feature from the Explorer forum main page for P0171 keyword and try the suggestions in the other threads you'll find there.
For all practical purposes, your Explorere is essentially the same as the 1997-2001 model years.
-Rod