Which car is cheaper to drive, accounting for mpg and gas prices?

Ok so my ford excursion is diesel and gets 14.5 mpg and diesel prices cost around $2.91. While my Honda Odyssey is gas and gets 21 mpg and gas prices are around $3.24. If it matters the excursion has a 44 gallon tank and the oddysey has a 20 gallon tank.

Read more: Which car is cheaper to drive, accounting for mpg and gas prices?