For several reasons, you can taste charcoal lighter fluid in your food. Your charcoal has too much lighter fluid in it. Another explanation could be that you sprayed the lighter fluid strongly, which caused part of it to splatter on the grill. While you continue to cook, the lighter fluid releases fumes attached to the food. It's also possible that you lit the lighter and immediately began cooking. The ideal time to wait is when the coals are covered in a thin coating of white ash. Ash is a sign that the coal has entirely burned out, and the lighter fluid has also burned off. If you use "fast light" charcoal, the lighter fluid taste can also happen.