Theres a few things to check. It gets confusing as both senders read same resistance and if the siphon is not working properly can cause some confusion. This is best way I have found to half split through the problem. Next time you are under half a tank go into the passenger side and pull the hat. Passenger side should be completely empty of fuel with half tank or less. If it is, good your siphon system works. While you have it open test and clean the sensor. Use a multimeter and read resistance. With the float arm down should read 15 ohms and slowly raise arm it should track up to around 160 ohms when fully raised. If all is good put it back in.
From here you now know the problem is with driver side sender or stepper motor problem in the cluster.
