2002 Expedition warning light/fuel issue

What is the warning light? Do you mean check engine or service engine soon light. Sometimes if the problem fixes itself or is manually repaired, if you don't turn the light off, it may or may not shut itself off after a certain number of warm-up cycles. What was the code you got, if any, from the light? If needed, did anyone scan for codes? 23k doesn't mean much, problems can crop up anytime, is this vehicle still under warranty? I believe federal law extends certain emission control components to 8yr, 80k miles.