Why am I experiencing a decrease in fuel efficiency in my Ford Fiesta?

I recently noticed that my Ford Fiesta's fuel efficiency has significantly decreased compared to when I first bought it. What could be causing this and how can I improve my fuel efficiency?

Sarah, it's possible that dirty fuel injectors are causing your Ford Fiesta's decreased fuel efficiency. Consider using a fuel injector cleaner to improve your car's performance.

Hi Sarah, have you checked your tire pressure? Under-inflated tires can greatly affect fuel efficiency. Make sure your tires are properly inflated.

Sarah, have you been idling your car for extended periods of time? This can also contribute to decreased fuel efficiency. Try to limit idling or turning off your engine if you will be stationary for more than a few minutes.