1998 Chevy 6.5 L starts runs fine turn off and won’t start
 

Sometimes the van will start and run fine then later that day it won’t start ...I’ve noticed the fuel gauge will peg itself way past full to the 3 o’clock position and won’t start . After a while I will turn key to start if the fuel gauge releases from 3 o’clock position it will start and run fine if it doesn’t release from 3 o’clock position it will not start ...puzzled ...I figure it’s some relay or something.....
any help is appreciated , thanks