How do you do a tune up to a 2003 Ford Expedition?

Buy a Chiltons service manual and it will help alot.

Change the motor oil, change the transmission oil and filter if it's been more than 30,000 miles since the last time, change the fuel filter, rotate tires. If the truck is around 100k miles or more, think about changing the O2 sensors (mainly the two front ones. I wouldn't worry too much about the back two.) First couple things that come to mind.

Also, I've tried looking for a Chiltons service manual for an 03, but I can't find one. Do they not make one?