How to fix low fuel efficiency in my Audi A8?

I recently noticed that my Audi A8's fuel efficiency has significantly decreased. What could be the cause of this issue?

First, make sure your tires are properly inflated and have the right amount of tread to ensure optimal fuel efficiency. Additionally, check your air filter and replace it if necessary. Another potential issue could be a problem with your fuel injector, in which case you may need to have it repaired or replaced.