Haven't driven this '88 LCS much in the last few months. Can't recall the last time I bought gas. I took a long drive today, several hundred miles. First thing was to gas-up, and seeing about 3/4 tank according to the gauge, I bought just a few gallons. To make a long story short, after a few hours, when the gauge read half-full, it felt like it was running out of gas. So, I put my 2 gallons of spare gas in the tank, and added 15 gallons ($60) at the nearest gas station. There was room for more... So it read half-full, but was empty. What's the simple procedure for re-calibrating this gauge?