Fuel Level 100%

& Fuel Remaining (100 gal) NEVER changes.  Instant Fuel Economy works. Fuel Rate works. Average Fuel Economy ALWAYS reads 3.6 mpg and Distance Remaining 364.2 miles.  Could it be in my Settings?  TIA, Chuck  2006 Cat C7

See the Getting Started document's 'Fuel and DEF' and 'Persistent Data' sections for information on fuel data.