As Pihl said, check the wiring since your dash gauge shows some sporadic activity. The ground for thr fuel sender is located under the floor just inside the rear wheel well on the driver's side. Should be a single black wire running to a binding post.

Also check the sender's positive wiring/main lead where it hook's up with the wiring to the dash. This connection is on the back of the same wheel well (driver's side rear).

Finally, pull the floor over the access panel to the sender unit/gas tank and take a look at the wiring connection on the outside of the sender cover plate (big white marshmallow looking hook-up). There is a gap of about 2mm between the marshmallow thing and the plate, and watercan get in that crack and rot/corrode/rust out the connector, effectively killing your sender assembly (the plate and arm that goes down into the tank).

If you do buy a new assembly (should only need a new one if that last condition has happened) make sure to caulk that 2mm gap at the plate o insure it doesn't rot out again.

Oh, on a sidenote, it is very obvious if your pre-pump is dead. Just open the gas cap and listen with your ear at the hole. If the pre-pump is working it will make a VERY obvious high pitched whirring noise. If you don't hear anything or don't "think" you hear anything its either shot or not getting juice.

good luck,
rt