It's hard to explain but I'll try. My dad told me about it. Mine did it for a while, except it was on 3/4 tank instead of 1/4. So anyways, there's a little ball/flotation device thing that is inside your gas tank. It measures how full your tank is...obviously. Well mine was weighed down and soggy, which will add weight correct? So it sinks further and further to the bottom...showing you that you have a certain amount of gas at all times, which isn't true. My dad told me to get a new one, but I don't know where to get one? Mine just kind of went away. It's fine now. Reads perfect amount of entered gas at all times. Sorry if that kind of gave you blue balls...ya know, lead you on but didn't finish! Damn I hate that. So anyways, I think you can find them at any local parts store, you may want to call around and/or ask. I would ask my dad but he's kind of out of town this week. It obviously didn't take him long, take it to Nissan (I know, EXPENSIVE)...either ask them how much one costs, how much it will take for them to fix it, or how long for a DIY project.