What is the most fuel-efficient engine option for the Ford Transit Custom?

I am looking to purchase a Ford Transit Custom, but I want to make sure I get the best fuel efficiency. Can anyone recommend the best engine option for this model?

I would recommend going with the 2.0L EcoBlue diesel engine. It has been proven to be the most fuel-efficient option for the Ford Transit Custom.

I have the 2.0L EcoBoost petrol engine and it's been great in terms of fuel efficiency. I would highly recommend it.

I've heard that the 1.5L EcoBlue diesel engine is also a good option for fuel efficiency and has a lower cost. Might be worth looking into.