So in the past couple of days, my 89 LX 5.0 has developed a strange tick. The gas gauge was reading the correct 3/4 tank on the way to work Thursday but when I left, it was pegged at full. While driving home (about 10 minutes) it very slowly started dropping back down but never reached the 3/4 tank mark. Since then, the gauge has read over full and hasn't moved. Any ideas what's happened? Sender? Gauge? Help!

 

might be a bad sending unit or it could be the anti/slosh module on the back of the cluster , i had the same problem it would go down but not anymore then under half a tank, i picked up a cluster from a junk yard and used the chip from that one i have had no problems since. hope it helps check i the chip first easier than droping the tank to check the sending unit , only to find out it was only that it was the anti slosh module