i get horrible gas mileage with my 1998 Expedition and I also have a problem with it eating oil by the quarts? by the time i need to change the oil again there's only about 4 quarts left in there?

anyways, i've always heard these things suck where gas mileage is concerned especially if there are any other emission issues going on. if you noticed a sharp decrease in gas mileage then keep your eyes open for your check engine light as there's probably something going on that just hasn't triggered the CEL yet.

good luck.