If you have a compressor, you might consider (while the Jeep is outside), removing the gas cap and putting 5-10 lbs of pressure to the metal line that feeds the fuel pump. If you hear bubbling in the tank, do the same thing with the front metal line while it is disconnected from the fuel filter.
Look along the entire length of your fuel line for wet areas, from the gas tank to the fuel pump. You may have to drop your tank to examine the rubber fitting that connects the fuel line to the sending unit/fuel pick up.
It is possible that even a brand new part can be defective.
I don't think there is a fuel pump in the gas tank of 1990 models. Mine is an '87 and it has only the fuel pump on the passenger side of the motor block. The parts catalog doesn't even show a sock in the tank.
Good Luck, L.M.