On my 1993 Eldorado, 4.9L, I replaced the fuel pump from the top without dropping the tank. It involved cutting a hole in the floor board. I know this was a very non-traditional/unorthodox method (required because my condominium rules prohibit jacking up the car in the parking lot), but it ended up being an easier method then dropping the tank.
In any case, information and pictures can be seen in the threads of the links below:
http://www.cadillacforums.com/forums...-bad-fuel.html ('93 Eldorado, 4.9L - Bad Fuel Pump?) http://www.cadillacforums.com/forums...-bad-fuel.html ('93 Eldorado, 4.9L - Bad Fuel Pump?)