04 Econoline 5.4 v8 using 2-3 quarts between oil changes calls for 5w-20 would using a thicker oil slow this down no leaks or noticeable smoke have been using high milage oil for the last 15.000 miles.
Using a thicker oil will not solve the problem, you'll just cause van to get worse gas mileage. The 5.4 engines are known to use a bit of oil, so you are in good company. Something you can try to do is change out the PCV or at the very minimum, clean the one you have to ensure you're not sucking up oil through the thing. Sometimes they get a little bit enthusiastic and can cause an oil consumption issue. Using the high mileage motor oil is not a bad thing to do.
If you look at your engine you may see where it's wet around particular places like the valve covers or front crankshaft seal. While it may not drip on your driveway, it may leak when running down the road. If you see a particularly wet area, you may want to see about getting the seal or gasket changed which corresponds.