renmur605, I hope this problem has been solved for you by now, but if not, there are three possible causes for this problem. 1. the gas tank sending unit is not operating properly and will require replacement. 2. the dash gauge itself is not operating properly and will require replacement. 3. you are not getting the tank full. The way to test 3. is to fill the tank until it runs out the filler tube, CAREFULLY! 1. & 2. require a mechanic that knows what he is doing by diagnosing electrical problems. My Jeep has the same problem and I have just lived with it for all these years. It gets to the 3/4 full mark and stops. If I had bought the Jeep new I would have made them fix it. My testing shows I have a bad sending unit, but dropping the gas tank to replace the sending unit it is more work than I want to do, hence, I just live with it.