Fuel gauge not working on a 98Z71

Fuses? Blown fusible link? Most gauges work by getting 12 volts from the ignition switch when on, and getting a ground from the sender. Often the 12 volt supply wire goes to more than one so if dead, both will fail. If you have a wiring diagram, you might find which wire to cluster should be hot, and trace it backward to find the issue. Easier to check for ignition switch feed first.

You probably have a bad fuel relay switch. It is located in the engine compartment in the fuse box. It costs about ten bucks and takes 2 minutes to change. I hate to say it but you probably didn't need a new fuel pump. If the relay is not the problem then it will be your fuel pressure regulator about $60. This part will affect your fuel gauge and cause intermittent starts and stalls or a no start. If your car sits for awhile the pressure will fall off and the car will start again but will not run well and it can stall out at anytime and not re-start.

The most common way to find out is to test both components.
The sending unit in most vehicles grounds the gauge on the dash.
You would unplug the sending unit - pump harness at the tank and ground the sending unit wire. If the gauge climbs up to full the sending unit is at fault.
You could also measure resistance in the circuit in the tank when the tank is close to empty and after filling it up. The resistance should be different each time.

If the sending unit was connected and grounded, I would guess the gauge in the cluster is faulty.

fuel lvel sensor is bad replace the fuel pump assembly,i work for GM

The guage stopped working, because a code set , possibly due to a faulty fuel sending unit, or a wiring issue. This would neeed to be scan tested for the current code. After repair is made, and the code is cleared, the guage will work again. Thanks...

This issue is probably caused by a faulty fuel sending unit or a bad connection by the gas tank. If possible try wiggling the fuel pump harness by the tank and see if gauge may start working.The particular harness I am referencing will contain a purple wire which is power wire to the fuel pump.This plug and harness also contains the wires that connect to the fuel gauge.This harness is located by the right rear tire by the gas tank.

The LS Lincoln Has 2 Fuel Pumps . The One On The Drivers Side Is Called A Transfer Pump , It Pumps Fuel From Drivers Side Of Tank To Passenger Side Both Pumps Have Sending Units On Them The Transfer Pump Sending Unit Was Bad

check to verify you didn't bump or unplug wire connections to fuel pump ,they are beside the fuel filter

I had the same issue with my 99 Silverado, The sending unit and fuel pump had to be replaced. (the fuel pump and sending unit are one piece units) Chevrolet dealers are aware of this issue, but its still not listed as a recall. I received a lifetime warranty w/labor when I had mine replaced. I also had an issue with the instrument cluster in dash that had to be sent out for repair unrelated to fuel gauge (speedometer)...also dropping the fuel cell is how mine was done also.

My guess would be the fuel pump purchased was bad...