Fuel Gauge started to act up with low fuel warning light staying on even though tank is full. Had a major tune-up (injects, plugs, wire, etc.) to include changing fuel filter and installing a new fuel sensor/sending unit with new fuel pump. No warning codes come up. Vette runs great it's just the warning light on cluster stays on. Mechanic is also puzzled. Is there an issue with the instrument cluster or a rely unit. Driving me nuts. Thanks.