tune up?

At what mileage is it recommended to give a 4Runner a tune up? I have a 1998.

See the "Maintenance Guide" on the following page:
http://www.edmunds.com/ownership/?tid=edmunds.g.home.header.own.5.*

On a 1998, the spark plugs should be replaced every 30,000 miles. Check the air filter. Other than that, fluid changes are important. The transmission fluid should be changed every 15,000 miles, the coolant every 30,000 miles, and the front and rear differentials and the transfer case fluid every 30,000 miles. Many dealers recommend doing the tansfer and diff. fluids every 15,000 with the trans fluid, but 30,000 is acceptable.