I admit to not being the greatest at math but I think it is underestimating. I have an 03 Sienna which we will be driving from NYC. It says fuel cost will be $280.88 round trip. The prices were $3.10 and over.Last night I had a little more than half a tank of gas. We filled up and it put in 8 gallons of gas at 3.19 a gallon. So I assume I have a 16 gallon gas tank. Since it takes about 200 miles for me to be empty, I calculated I get 13 miles to the gallon. When I try to figure gas costs, I estimate about $550.00 to get to and from Orlando. What am I doing wrong??

A 2003 Sienna has a 21 gallon fuel tank (20.9, but who's counting?) and is estimated to get between 19 and 24 mpg (city/hwy). If you are not getting these mileage averages when you drive, you might want to consider taking your van in for an oil/air filter change and a look-see before your trip. Good luck!

We just had an oil change but someone told my Dh it may need to be calibrated. I will check that out- thanks.