What is the best way to improve gas mileage in a Ford Transit Custom?

I've been driving my Ford Transit Custom for a while now and I've noticed that my gas mileage isn't as good as it used to be. What are some tips or modifications I can make to improve my fuel efficiency?

One easy way to improve your gas mileage in a Ford Transit Custom is to make sure your tires are properly inflated. Under-inflated tires can reduce fuel efficiency by up to 3%

Another important factor is driving habits. Avoid sudden acceleration and braking, and try to maintain a steady speed. This can greatly improve your gas mileage.

You can also consider getting a tune-up for your engine. Dirty air filters and spark plugs can greatly affect your fuel efficiency, so it's important to keep them clean and in good condition.