My 2012 Pro4X only fills w/16.5 gallons of gas when on Empty (21 gallon tank). Could you take 5 seconds now and reply how many gallons gas you can put into your empty Xterra tank? The replies I get can help inform my tank issues. In your reply, please list the gallons, and your Year & Model Xterra. Thanks, Xterra community! You all are the best. -adolphi