Im having a trouble figuring out why my gas gauge only read half full when topped off and empty with 5 gallon still in the tank. I have a late model cj 15gal plastic rear mounted gas tank with a mts sender and autometer gauge in the correct ohm range. I dropped the tank yesterday and took the sender out and connected the sender wires. The gauge seemed to read correctly when moving the float by hand but once reinstalled into the tank it wont read higher than half. Im going to pull the tank out again this weekend, how should i check and adjust the sender and gauge?