What is the cause of poor fuel economy in the Audi A4?

I've noticed that my Audi A4 is not getting very good gas mileage. What could be causing this and what can I do to improve it?

The most common cause of poor fuel economy in the Audi A4 is a dirty air filter. Make sure to regularly replace your air filter to improve your gas mileage.

In addition to a dirty air filter, low tire pressure can also contribute to poor fuel economy in the Audi A4. Check your tire pressure regularly and inflate as needed.

Another potential cause of poor fuel economy in the Audi A4 is a faulty oxygen sensor. Consider getting it checked and replaced if necessary.