RonD.

Fuel gauge only goes up to 3/4 mark when full. After sufficient miles driven to lower fuel level gauge will still read 3/4. Now when cold start gauge reads proper estimated fuel level based on miles driven and then slowly goes back up to the 3/4 mark after warming up. Fuel gauge faulty? or fuel level sender unit? in gas tank.

Northern_aqs

Possible to be either. Best to pull the trunk carpet, the sender and test the resistance through the full sweep. My experience is that when the sender fails it fails outright and when it's ground/connection related, it mis-reports levels.