After I drained or substantially pumped out the tank, I proceeded as follows (97 CVPI):
Back the rear wheels onto a pair of ramps or otherwise raise the rear of the vehicle.
Disconnect the spring-lock fuel supply and return connectors using the appropriate expander tool (Lisle makes a good cheap set).
Disconnect the electrical connector (this isn't actually too hard).
Remove the screw retaining the filler tube to the tank.
Remove the screws securing the upper fuel filler tube to the left rear body panel.
Remove the nuts from the two tank retainer strap studs.
Gently lower tank to ground.
When re-installing tank, you may have to replace the tank strap retaining studs witn new ones. This is because the original studs may have been intentionally broken off at vehicle assembly
to avoid punctures.
Re-connect your lines and electrical harness when complete. Hope this helps.
1997 Crown Victoria P71 (former UMaryland security).
2008 Crown Vic P71 (former Sault St. Marie, Ontario PD).