same here. I have a 05 cargo van with the 4.2 and the gas milage is awful. It doesent have a trip computer but i usually get 500-550 per tankful. The tank holds 100 liters . My 05 f 150 has a 114 liter tank and goes 745 per tank. Amazing that a 4 door four wheel drive pickup can get better gas milage than a mini van. No complaints on the van however. It has tons of power and has been a very reliable vechile so far. I have to trade it in soon on a 2007 and am hoping to get another one if there are any left | 
