I just bought a 2005 Grand Cherokee Laredo Rocky Mountain 4.7L V8 with 98,000 miles. The dealer is saying that it should get 16/17cty and 20/21Hwy. However, I've driven roughly 90 miles combined in the 4 days I've had it and the MPG average indicator says I'm only getting 13.3 right now. That is with 40 highway miles and the rest stop and go city. Should I take it back and have them fix something or is this what I should be expecting, in which case I will be trading it back for something smaller like a patriot. Driving for work I will be filling it about every other day and I cant afford that.