Si1i3

Hey i have a 1988 s13 ca18det manual with the digital hud cluster. I took the ar away for new years and filled it right to the top for the first time ever. Now the gauge won't go below 3/4 even though I'm 100% sure i have nowhere near that left. Have tried resetting the ecu, no luck and am wondering if this is a common problem and how to cure it? When cornering the needle goes right up to full but never down past the 3/4 mark.

Please help