2004 cavalier gas gauge problem

Hello I have a 2004 cavalier and the gas gauge on it is spiked all the way over and holding down the temp gauge. It does not hurt the temp gauge, I still have heat. I have noticed that after I drive the car for a little bit then shut off the car for a few mins. and start it back up the gas gauge will move down a little to it's normal spot but it still way past full. If I do that a couple times through out the day it will eventually go back to where it should be. But the next day it will go back to past full again. I have tried unhooking the battery to reset it and it works for a day or two then goes right back again. If there is anyone that can help me with this problem. Thank You

stepper motor bad go to salvage and get one i did and bought whole cluster for $35 and bought extra to this will fix it u wont lose your mileage built in pcm