So around a month ago i bought a 2002 mustang GT with roughly 80K miles with a swaped motor that the man claims have 65K on it and claims that the cluster wasnt swaped either but who knows besides him. Also no paper work for the swao. Before i bought the car during the test drive the gas gauge read 3/4 of a tank. After putzing around the block a few times after i bought it and finally put gas in it the gauge read full which made me happy. But now the gauge doesnt move from full but when it does it goes to right under full line. I am afraid to drive it untill the gas light comes on because i dont know if it will. I dont know the issue and am afraid to have a crack at the cluster since i wouldnt have a clue what im looking at hence im new to cars. I looked up a few videos and cant really get down what i need to do to fix it. Please help me figure out my problem.