Why is my Vauxhall Insignia's fuel economy decreasing?

I have a Vauxhall Insignia and I've noticed that my fuel economy has been decreasing over the past few months. What could be causing this and how can I improve it?

One possible reason for a decrease in fuel economy could be a dirty air filter. Check your air filter and replace it if it's dirty.

Another reason could be low tire pressure. Make sure to regularly check and maintain the correct tire pressure for your vehicle.

If your vehicle is due for a tune-up, that could also affect your fuel economy. Make sure to schedule regular maintenance to keep your car running efficiently.

Changing your driving habits can also help improve fuel economy. Avoid aggressive driving, accelerate and brake smoothly, and use cruise control when possible.