2003 4.4 (hers) gets 23 on highway (24 if no mtns to run in) and about 19 on the OBC with city and highway combined. With perfect conditions on Interstate speed limit driving we can get almost 600 miles per tank.

2003 4.6is (his) got 20 mpg on a combined hwy/town/twisty turny 4000 mile road trip last fall. MPG goes down the faster you go (like 85 vs 75mph) because it has a lower gear ratio than the 4.4. 75 mph at 2500 rpm on the 4.4 vs 75 mph at 2950 rpm on the 4.6.